Darwin local James McDonald and his friends were making their way along a waterway known as East Alligator River (a misnomer since Australia has no native alligators) in Kakadu National Park, when they spotted a dead crocodile floating in the water – and it wasn't alone.

McDonald caught the scene on camera: the living croc (let's call it Hungry Croc) pushes the Dead Croc around for a while before getting a good grip on Dead Croc's tail and flinging it violently through the air, presumably aiming to tear off a big chunk to swallow. McDonald said in an interview with NT News that the group had also witnessed Hungry Croc biting pieces off Dead Croc earlier in the day.

It's tempting to imagine that what we're witnessing is the end result of a croc fight, but crocodile expert Adam Britton says that would be unusual. "Crocs can be aggressive towards one another a fair bit, but usually the encounters are brief, with one chasing away another," he said via email. "If these encounters do prove fatal, the victor may take a few bites of the loser, but they generally leave them alone."

It seems even more unlikely that Hungry Croc would have killed Dead Croc for dinner. Crocodiles make for dangerous prey, and it's very risky for one of these carnivores to go after another of similar size. On the other hand, Britton points out that there are plenty of even bigger crocs on the river, and Dead Croc looks like it's been chewed up a good bit already. Perhaps Dead Croc got on some giant's bad side, and Hungry Croc was simply picking up the leftovers?

Because the carcass seemed well on the ripe side by the time the flinging scene took place, McDonald guessed Hungry Croc may have left its spoils out to rot and soften – but this isn't really the sort of thing crocs do.

"There is actually no evidence that they cache food, or leave it to rot," Britton explained. "These are extremely strong animals that can rip limbs or flesh off by flicking the head (as you see in the video) or twisting it off by rolling. They don't need to wait for it to rot."

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Top header image: Ørjan Lillevik/Flickr

Remember when we awarded the honorary "Guillermo Del Toro" award to this eyeless goby? Well, we may have to reassign the title...

This alluring looker, dubbed the "faceless fish", was hauled up by scientists onboard the CSIRO research vessel Investigator during a recent expedition to explore deep-sea habitat from northern Tasmania to central Queensland.

An international team of 40 scientists is on a month-long voyage to study life in Australia's eastern abyss: a dark, mostly uncharted habitat found 4,000 metres below the surface. "We know that abyssal animals have been around for at least 40 million years, but until recently, only a handful of samples had been collected from Australia's abyss," notes Dr Tim O'Hara, senior curator of marine invertebrates at Museums Victoria and chief scientist of the "Sampling the Abyss" mission.

While there isn't much information available (yet) about this latest strange-looking find, it didn't take online commenters long to jump to some familiar Fukushima-related conclusions:

Here's what we do know:

The fish is not a radiation mutant, and in fact, this likely isn't the first specimen to make an appearance in the region. According to Museums Victoria senior collections manager Dianne Bray, a fish of similar description was caught by the crew aboard the HMS Challenger back in the 1870s, in the Coral Sea off Australia's northeast coast. However, we don't know enough at this point to suggest the odd creatures are endemic to the region. 

Our own best guess is that we're looking at some kind of cusk-eel (the same family as this bizarre bony-eared assfish).

Despite appearances, the fishy find does actually have a face. Its featureless visage mostly comes down to its reduced eyes, which are common in the deep sea since sharp vision is no asset in a place where so little light penetrates. We see this same evolutionary pattern in fishes that inhabit caves or muddy streams. 

Along with John Pognoski of the CSIRO Australian National Fish Collection, Bray will be working to identify the fish over the coming months. Aside from the exciting possibility of discovering new deep-sea species, surveying these abyssal areas is important for other reasons, too.

"The data gathered on this trip will be crucial to understanding Australia's deep-sea habitats, their biodiversity and the ecological processes that sustain them. This will assist in its conservation and management, and help to protect it from the impacts of climate change, pollution and other human activity," explains O'Hara.

In the days since this strange fishy haul, RV Investigator has encountered even more specimens out on the open ocean.

"We reached our next sampling site off Newcastle this morning and put down a beam trawl to 4,000 metres," Investigator's onboard communicator Asher Flatt said in a trip update. "There was much excitement once the trawl came up as more faceless fish came up with it, some of which were nearly see-through. It looks as though it may be a new species!"

We'll be updating you on these finds as more information comes to light, so watch this space!

UPDATE (May 31, 2017): Eel expert John Pogonoski tracked down the ID of the faceless fish while working his way through various scientific publications. The fish is indeed a type of cusk eel: its scientific name is Typhlonus nasus (from the Greek "typhlos" meaning "blind" and "onos" meaning "hake" – a blind hake). 

"It’s not a new species, but it’s still an incredibly exciting find, and we think ours is the largest one seen so far. Although very little is known about this strange fish without a face, it does have eyes – which are apparently visible well beneath the skin in smaller specimens," writes the team in a blog update.

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Top header image: CSIRO's RV Investigator (Mal Booth/Flickr)

The clash between a free-swimming squid and a group of brittle stars was captured during a dive off the coast of Jarvis, an uninhabited coral island about halfway between Hawaii and the Cook Islands. This kind of interaction is so rarely seen that it's been filmed only once before.

"[This is] one of the most amazing echinoderm-related natural history moments that I've seen in a while!" writes starfish expert Dr Christopher Mah on the EchinoBlog. 

Unlike true starfish, which hover around atop hundreds of tube feet, brittle stars (or "snake stars") can move quite quickly across the seabed – their superior motoring comes down to those long, wriggling arms – but even so, these creatures are largely known as scavengers or filter feeders. 

After watching the clip, some online commenters suggested that the stars didn't actually eat their cephalopod captive, but Mah assures readers that the meal was indeed devoured. In fact, he points out, similar behaviour was caught on camera back in 1996:

Just as in the video above, chances are the various stars involved in the Okeanos catch got a chance to tear off a chunk of leftover calamari. In brittle star communities, it seems, sharing is caring. 

"Spines in these brittle stars are sharp and often with jagged edges ... so capturing something soft-bodied isn't too surprising," writes Mah.

The Okeanos team hopes that this and other records from their dives around Jarvis will shed some light on how offshore communities here rely on one another. Much of this region has yet to be mapped – in fact, large swathes have never been seen by human eyes. 

"These are the kinds of behaviours that you would never see in a textbook," says the team. "It really takes getting down there and watching."

For more on the interaction, including a closeup of brittle star teeth, head on over to the EchinoBlog!

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Top header image: Patrick Randall/Flickr

This striking pair of images has racked up over 250,000 shares on Facebook alone in the days since the South Texas Hunting Association (STHA) shared the snaps to their page. According to STHA, the "13-pound" (5.8kg) frog was landed by local resident Markcuz Rangel at a Texas ranch.

Whether Rangel was after frogs or fish is unclear, but frogging is a popular sport in the area, and Rangel has snagged some sizeable bullfrogs in the past.

But here's the problem: at an average weight of just one pound, bullfrogs in North America don't even come close to the STHA's multipound claim. In fact, the largest frog in the world – the Goliath frog, which reaches about seven pounds – is still far smaller than Rangel's alleged catch.  

And why the long face? This amphibian's appearance is being distorted by forced perspective (the same optical illusion that turned a healthy wolffish into a "supersize Fukushima mutant" back in 2015). 

Bringing the frog closer to the camera lens ensures the creature looks far larger, especially when viewed with Rangel's more distant form in the background. This is actually the very same trick that was used to make Frodo Baggins appear small in Peter Jackson's Lord of The Rings trilogy.

So, is this a real, big bullfrog?

"It's still a big bullfrog," agrees Texas Fish and Wildlife in an interview with local news outlet Chron.

But we're calling "bull" on the 13-pound chart-topper.

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Top header image: Mecki Mac/Flickr

Just this month, a new report revealed the status of another predator expanding its European territory: the golden jackal. These canines have spent the past few decades establishing themselves in various countries across the continent. Now, it appears they've made it to northern Germany.

Golden jackals were once more widespread across Europe, but as humans continued to expand and swallow up wilderness, the species disappeared from some of the countries it called home, and found itself restricted mainly to the east. By the end of the twentieth century, however, the jackals were regaining territory, appearing in Hungary, Ukraine, Austria, Italy and elsewhere. They've even started settling in countries with no historical record of their presence, such as the Czech Republic.

Germany is no stranger to the jackals' northward march. The animals were spotted in Brandenburg as far back as 2002, and in more German states since. Just this month, an individual was found dead on a highway in southern Germany, not far from the Munich airport. The northernmost parts of the country are made up of Mecklenburg-Vorpommern, where jackals were caught on camera last year, and Schleswig-Holstein, where they were spotted for the first time this month.

Earlier in May, a farmer reported three sheep killed by a predator along the Baltic coast, and asked for governmental compensation. Authorities initially suspected the classic sheep-nabbing culprit: grey wolves (which have also been making a comeback in Europe). But a DNA sample revealed the presence of golden jackals in the area.

German officials aren't yet sure if this particular jackal migrated over from the north, or moved in from another part of Germany. To the north, Schleswig-Holstein borders Denmark, which just a couple of years ago became the northernmost jackal outpost. 

Golden jackals aren't much like their distant canid cousins in Africa. The species is much more closely related to wolves and domestic dogs – in fact, they're known to hybridise with them. The animals are extremely adaptable, living in a variety of habitats and eating pretty much anything that's available, from fruit to small animals to livestock. Most of the time, these carnivores live with their mate and offspring, so if you see one golden jackal, there's a good chance there are more.   

Its spread across Europe has brought up questions about whether the species belongs in places outside of its known historic range, and some locals are worried about the impact these new arrivals might have. As you'd expect, farmers in particular are concerned for the safety of their livestock. In some countries, golden jackals are killed for this reason, but in Germany, and much of the rest of their range, they're protected by law. Many are now wondering how best to co-exist with these animals – especially because it appears they're here to stay.

The main culprit behind the jackals' surprising expansion? It seems to be … us! While industrialisation and urbanisation had a hand in the decline of these predators in the first place, in more recent years, human activity has resulted in a changing landscape, the removal of other large predators (like wolves) and increasing global temperatures, all of which are boons for golden jackals looking for a new place to stake their claim.  

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Top header image: Peter Steward/Flickr

This clash of cetaceans was filmed in California's Monterey Bay, the same coastal hub where we watched a pod of orcas feast on a grey whale recently. 

"Although humpbacks stand up to killer whales and trumpet blow at them, blue whales are easily startled and flee the scene!" explains the team at Monterey Bay Whale Watch, who uploaded the drone footage to their Facebook page this week. 

The blue whale could be seen "porpoising away, swimming at full speed out of the water," the team adds.

Monterey Bay hosts Biggs (previously known as "transient") orcas, a group that specialises in hunting marine mammals. Despite those predatory skills, however, the blue whale wasn't in much danger here. We are, after all, talking about the largest animals on the planet, which can grow to a mind-boggling 110 feet in length. And even newborn calves weigh in at several tonnes. 

An orca charge of this nature has been observed only once before in the bay. That encounter involved a juvenile blue whale, and the youngster still managed to thwart its attackers with a powerful tail throw. 

"Some of our blue whales do have killer whale tooth rakes on them," says the team. "Especially on their flukes, pectoral flippers and dorsal fins. Blue whale attacks have been documented in Mexican waters, but we have not documented any killer whale attacks on adult whales – except for minke whales, which are our smallest baleen whale in the Northern Hemisphere."

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Top header image: Dave Govoni/Flickr

When an Indo-Pacific bottlenose dolphin known as "Gilligan" washed up dead on Stratham Beach near the city of Bunbury back in 2015, the culprit was painfully obvious.

Researchers from Murdoch University's College of Veterinary Medicine conducted a necropsy on Gilligan, and a closer look at the otherwise healthy cetacean confirmed the team's initial suspicions: seven octopus tentacles were stuck to the back of the dolphin's throat.

"Rangers on Penguin Island and staff of [a] nearby ecotourism company ... have anecdotally reported similar octopus-related deaths in the past in both dolphins and Australian sea lions," write the researchers, who recently published their findings in the journal Marine Mammal Science. "Some have even recounted stories of having seen, in some instances when dolphins were observed holding an octopus in their mouths, the apparently live octopus reaching up towards the dolphin's blowhole."

Toothed whales can actually dislocate the larynx (or airway) to help them swallow large, awkward prey – but that's a risky manoeuvre because it breaks the seal that separates the lungs from the oesophagus. In this position, prey can move freely into the nasal passage. We saw that rare mishap last year when a pilot whale was asphyxiated by its flatfish dinner.

In Gilligan's case, however, death by suffocation occurred a bit differently: the octopus's powerful tentacles had indeed moved the larynx out of place, but they also flattened it, much like what would happen if you kinked a garden hose. This pinch would have prevented any air from reaching the lungs – even with the octopus sitting safely in the food pipe.

After removing both the airway and oesophagus from Gilligan's body, the researchers also discovered "innumerable circular lesions, many of which were discoloured red-purple." The suckers were holding so firmly that they gave Gilligan "throat hickeys" – impressive given that the octopus's brain was completely detached from the appendages.

"The real problem is that these arms stay active even after an octopus has been mortally wounded," explain Kate Sprogis, and David Hocking, who study Western Australia's cephalopod-slurping dolphins, but were not involved in the necropsy. "So even while a dead octopus is being processed, the suckers may still be able to find something to stick onto." In fact, lab tests have found that an amputated octopus arm may stay active for up to an hour after the animal dies.

Dolphins are certainly better breath-holders than humans are, but not by much. When swimming slowly at the surface, a typical adult dolphin will breathe between two and five times per minute – and exertion during hunting (or fending off a counter-attacking octopus) ups their need for air. In fact, experts have never observed a dolphin holding its breath for more than eight minutes.

"Despite this considerable ability, the dolphin would have been no match for the octopus's tenacity, and it is unknown how long this individual might have struggled to free its larynx from choking before succumbing," says the Murdoch team.

It's also possible that Gilligan died from cardiac arrest before he ran out of oxygen. The fight-or-flight response is known to release excessive amounts of the protein catecholamine in dolphins and their mammalian kin, including humans. This can have a direct toxic effect on the myocardium, the muscular tissue of the heart.

Clearly, octopus is a risky item to have on the menu, but new research does hint that dolphins have developed a few tricks to make it safer to eat.

The animals' simple, blunt teeth aren't meant for shearing, so individuals in some Australian pods opt for a "shake and toss" strategy when hunting octopuses. The manoeuvre is certainly effective at stunning and killing the dangerous prey, but local scientists are beginning to suspect it also makes those unwieldy suckered arms safe to swallow by "tenderising" them into submission. 

"Assuming an octopus carcass is sufficiently processed to render its arms into small enough fragments such that they and their suckers can be effectively and safely swallowed, their consumption must generally be a risk worth taking," the researchers note. "Although it did not play out well in this individual's case."

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ht: New Scientist 

Top header image: saspotato/Flickr

The findings come from a collaborative citizen-science project overseen by South African National Parks (SANParks). With the help of rangers and aerial surveillance teams, park staff used over a decade of visitor-submitted photos and video to locate big tuskers within the two-million hectare park.  

"Any elephant with remarkable tusks (more than 1.5 metres from the lip line) is of interest," says the team. "Individual elephants are then identified by their ear notches and any unique features (scars, swellings, etc.) they might have."

A dozen of the 28 elephants assessed meet the criteria to be considered "potential tuskers", an awe-inspiring group of bulls that will now be closely monitored.

Because they typically weigh more than 50 kilograms (110 lbs) each, the tusks of such elephants fetch staggering prices through the illegal trade. Just last year, Kenya's Tsavo East National Park lost one of its iconic big tuskers, "Satao 2", to a poaching attempt. His predecessor – once thought to be the largest surviving tusker in Kenya – was also killed by poachers. 

"When a new tusker is identified we currently name it after a ranger or other member of staff who has given many years of service to the Kruger National Park," says the team. "It is traditional for rangers to be given an ethnic title by their colleagues and staff, and it is these 'nicknames' that are used for the tuskers."

This convention has been in place since the death of the so-called "magnificent seven", a group of tuskers that roamed Kruger over thirty years ago. 

"The public reaction to the 'magnificent seven' was staggering," says SANparks. "When each of these great elephants died, it was decided to retrieve their tusks and skulls in order to display them."

Kruger's tuskers have for years captivated visitors to the flagship park, but they have also captured the attention of big game hunters eager to land a sizeable trophy. Timbavati Private Nature & Game Reserve – which shares a fenceless border with the Kruger Park – made headlines recently following news of a controversial permit signed off by SANParks to hunt a trophy bull on the reserve.

Timbavati relies primarily on hunting permits to fund their conservation initiatives. Although the contentious strategy has drawn criticism, the reserve can boast strong wildlife numbers and minimal poaching. Records do show a trophy elephant on the hunting quota, but Timbavati Warden Bryan Havemann insists that Kruger's tuskers are not at risk and has the records to back it up: in the last ten years, the heaviest tusks of a hunted elephant on record weigh in at 60 pounds, which is not tusker territory.

Big-tusked elephants will always be in demand by hunters and poachers, and the Timbavati controversy serves to highlight the importance of putting effective conservation policies in place to protect these unique behemoths.

With any luck, the newly identified group will be joined by even more tuskers in the coming years – a conservation win that will only be possible with continued submissions from dedicated citizen scientists. Anyone who encounters an elephant of interest is urged to submit both photos and video footage using the link provided here. 

"Be patient, the animals may not move or behave the way you wish they would," says the team. "Please remain a safe distance away at all times." 

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Top header image:

These reptilian predators are not exactly known for being social creatures: the image of a solitary serpent is pretty typical. Yet some species do gather in groups for mating and hibernating, and some are even known to take care of their eggs. Now, a new study has revealed yet another unexpected social behaviour.

In March 2016, Vladimir Dinets of the University of Tennessee in Knoxville spent eight days observing the hunting habits of Cuban boas. These snakes live almost exclusively on their namesake island, and are one of the largest snake species in the West Indies. Their diet includes birds, rodents and lizards – but when the boas get a hankering for furry fliers, they crawl up the wall of a cave and catch bats.

Coordinated hunting is pretty rare throughout the animal world, and has never been definitively observed in a snake species before. But in a sinkhole cave in Desembarco del Gramma National Park, Dinets saw snakes working together as they went after Jamaican fruit bats.

His is the first study to scientifically test the assumption of coordinated hunting in any reptile. 

Now, we know what you might be thinking: you've seen snakes hunt in groups before. Perhaps you remember the swarming sea kraits from Planet Earth, or the even more infamous gauntlet of racers that terrorised an intrepid iguana in Planet Earth II:

However, experts argue that these snakes weren't truly working together – they were simply hunting the same prey in the same spot.

"To confirm that coordination does occur," Dinets explains, "one has to demonstrate that the predators take each other's position and/or actions into account, rather than simply gather in the same area."

The cave that Dinets staked out was host to nine Cuban boas, ranging one to two metres (3-6ft) long. Around dusk and dawn each day, one or more of the snakes would find a comfortable place on the ceiling to hang out just before the few hundred resident bats started their twice-daily flights in and out. The snakes didn't choose these hunting spots randomly – they kept each other in mind.  

For as long as Dinets watched, every time multiple snakes came out to hunt at the same time, they would settle nearby each other. With two or three snakes in position, they formed an unsettling "curtain" of predation draping across the two-metre-wide (6ft) cavern. The more snakes turned up, the more fruitful the bat-hunting.

"They position themselves in a way that allows them to form a barrier across a cave passage," Dinets says. "This significantly improves the effectiveness of the hunt, apparently because they can most effectively block the prey's flight path and easily intercept passing bats."

At times when three snakes were out together, they each typically managed to grab a meal within just six or seven minutes. With only two snakes, it took ten minutes on average. And the three instances Dinets watched snakes hunting solo, one of them managed to catch a bat after an exhaustive 19 minutes, and the other two failed completely and gave up after almost half an hour of trying.

Dinets explains that one snake is easy for bats to avoid, but two or three snakes close together, blocking the passageway, leaves their flying food with fewer options. The serpents aren't exactly pack hunters, but the fact that this behaviour is so consistent, and that it significantly improves the snakes' hunting odds, suggests this teamwork is no accident.  

"This possibility suggests that at least some snakes are not the 'solitary animals' they are commonly considered to be, and that they are capable of high behavioural complexity," he says. 

But are Cuban boas the only snakes that do this? It's difficult to say, since most snakes' hunting tactics are not very well understood – after all, it takes a lot of waiting in the wild to see a snake grab a meal. On top of that, these island snakes are becoming more and more difficult to study as their numbers dwindle in the face of hunting by locals.

"I suspect that if their numbers in a cave fall, they can't hunt in groups anymore and might die out even if some of them don't get caught by hunters," Dinets worries. "A few of these caves are in national parks, but there's a lot of poaching everywhere."

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Top header image: Shutterstock

The footage, which was posted to the Latest Sightings YouTube channel this week, was filmed at Leopard Creek Country Club near Kruger's Malelane Gate.

"At first glance, I thought it was a spitting cobra that had its hood up," says contributor Cara, who filmed the encounter. "I then saw it was actually two mambas. I quickly flagged the other two players in my four ball to slow down.”

This behaviour is often confused for mamba mating, and we've seen it before – most recently during a similar encounter back in 2015:

Both local herpetologist Johan Marais and snake expert Shaun Bodington explain that the twisting brawl is usually a show of bravado between males. By repeatedly trying to top one another, the snakes prove their worthiness as a fit mate. And much like in a human wrestling match, the weaker of the two eventually bows out. This is precisely what golfers witnessed at Leopard Creek.

"It was amazing to watch and seemed to go on for ages," says Cara. "We debated about carrying on playing the hole, but after a little while longer, we decided to drive past them at a wide berth and go to the next hole."

The golfers made the right call: while mambas aren't the people-chasing aggressors they're often made out to be, these snakes are highly venomous and should be treated with respectful (and extreme) caution at all times. 

After a lengthy spat, the two males separated and slithered back into the bush – the victor likely headed toward a lurking female. "We found concentrating on golf quite difficult over the next few holes," Cara recalls. "I feel this was a once-in-a-lifetime sighting. Always make sure you have a camera on this golf course!"

Top header image: Tad Arensmeier/Flickr

(Protip: The best stuff happens after Rajput’s cameo at 00:56)

“This is a real knock-down, drag-out fight, probably between territorial males,” explains Dr Richard D. Estes, a biologist specialising in mammal behaviour. “Muzzle-wrestling is the modus operandi.” 

Striped hyenas (Hyaena hyaena) are dog-like omnivores that roam north and east Africa, the Middle East, central Asia and the Indian subcontinent. The scraggly species sports black stripes that cut through a shaggy beige or grey coat accented with an impressive crest of hair – which stands erect when the animal feels threatened. 

This particular tussle meets all the criteria of a turf war. When striped hyenas fight, they usually attack each other’s cheeks, neck and rump, sometimes dropping to their knees to protect their vulnerable front limbs. Like many other territorial animals, the species uses scent-marking to claim its domain – and in typical hyena style, it’s pretty vile. The hyenas smear grass stalks with a pungent paste secreted from an anal pouch, letting the neighbours know when they’re home.

If a rival hyena ignores the malodorous goop and crosses enemy lines, dramatic fights can break out, and much neck-nipping and face-wrangling ensues. The very bold stripe pattern visible on both individuals in this footage might be another clue that this is a territorial dispute. “It suggests an excess of testosterone,” says Dr Este, explaining that the striping is exaggerated when males are feeling particularly macho.

The social lives of striped hyenas are still a bit of a mystery, but some experts speculate that they have a similar family life to the less striking brown hyena. Much like their unkempt cousins from the south, striped hyenas are solitary foragers, but they do seem to enjoy a bit of company on occasion. There are records of the species associating with family groups, and subadults have been recorded taking food to younger siblings at a central den. It’s still unclear, however, if the species prefers communal living on a full-time basis.

These pointy-eared bone crushers are usually seen alone, and they rarely emerge outside of their nightly foraging hours, making Rajput’s sighting all the more special. Much of what we know about the species comes from the well-studied African populations, so sightings like this one can play a part in helping experts figure out if the ecology of Asia’s hyenas differs from that of their cousins on the desert plains of north and east Africa.

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Header image: Jenis Patel

The megamouth shark is so rarely seen that its existence eluded us until 1976. To this day, the species is officially known from just 102 specimens. We've yet to discover where these creatures give birth, exactly where they live, or even how many of them are out there. But just recently, divers off the coast of Japan managed to free one of the lumbering giants after it swam into a fishing net.

This amazing clip was filmed by local resident Hiroyuki Arakawa during a dive in the waters off Chiba, a prefecture of Japan located on the island's east coast. While the sizeable shark looks scary, Arakawa and his fellow divers were in no danger here.

Like so many of the ocean's largest inhabitants, megamouth sharks (Megachasma pelagios) use their 50 rows of tiny teeth to sieve krill, small jellies and other plankton from the surrounding water – and those dietary preferences likely had something to do with how this individual landed in a midwater net. 

The colossal fish are known to dive up to 1,500 metres beneath the surface, but their krill prey regularly migrate from deep to shallow water. Scientists suspect that megamouths follow suit: spending the daytime hours in the depths and ascending to mid-water at night to feed. The composition of their liver oil, which helps sharks stay buoyant, also supports the hunch that they clock ample time in the shallows. 

This particular shark was first seen by fishermen in the early hours of the morning, so it likely became trapped during a midnight snack gone awry. 

After news of the entanglement began circulating locally, fish researcher and TV personality Sakana-kun, who is also a professor emeritus of the Tokyo University of Marine Science and Technology, instigated rescue efforts. The stunning female – estimated to be between five and six metres (about 20ft) long – was moved to a safe area of open ocean using an underwater guide cage. 

More so than any other country, Japan is the place to spot megamouth sharks – and even so, only about 20 sightings exist on record for the region. Most of these cases were similar entanglements, and very few of those sharks survived. In fact, only two living megamouth specimens have ever been studied by researchers, so this successful rescue is a big deal for science.

"My dream has come true," Sakana-kun told local news outlet Asahi. "I could see her vigorously swimming." 

Unlike great whites, megamouths don't need to keep swimming in order to breathe: instead, they can move oxygenated water through the body by gill pumping. In entanglement situations, that certainly improves their chances of survival, but these incidents can still prove fatal if the sharks become really stuck. We also don't know how long the sharks can run on gill pumping alone.

Back in 2015, a 5.5-metre megamouth was killed by a fishing net in Albay's Marigondon port. That encounter marked the 15th sighting for the Philippines – but whether or not the area is a true "hotspot" for the sharks remains unclear. 

When it comes to popular megamouth hangouts, some point to the western Pacific – but it could be that sightings in this region are simply more common due to its topography and extensive local fisheries. Specimens have been found in all major oceans over the years, so it's quite likely that these animals are cosmopolitan travellers.

UPDATE (May 24, 2017): Just a day after it was rescued from fishing nets, the megamouth shark featured in this article was found dead on the seabed. Sakana-kun, a professor emeritus of the Tokyo University of Marine Science and Technology, confirmed the death with local news outlet Asahi. "It is regrettable,” he said. "Having seen her on the previous day I thought she was going to become energetic."

UPDATE (May 25, 2017): After speaking with several local marine biologists, we can confirm that the megamouth shark's body has been collected for preservation. None of the information we have received thus far supports allegations that this shark was moved into a guide pen strictly to provide entertainment for divers. The exact hold-time and specific location of the shark's death, however, remain hazy. 

"It was transferred to the offshore pen, and filmed and photographed there," says Dr Kazuhiro Nakaya, a professor emeritus at Hokkaido University, who wasn't directly involved in the relocation efforts. "The body has already been frozen by Kamogawa Sea World for scientific investigation, and we are going to make some investigation in near future."

Analysis of the shark's tissues may reveal a clearer cause of death. The stress of capture in the net and pen may certainly have been a contributing factor, but that is speculation at this point.  

Some online commenters have surmised that time in the pen prevented the large shark from breathing properly. Nakaya explains that while this is possible, we really don't have the information to make that claim. As noted in this article, data from one megamouth shark suggests that the animals can – to some extent – breathe without swimming forward.

"The megamouth shark is a member of the salmon sharks in the broad sense," he says. "And they are generally adapted to offshore waters, always swimming. They take the water for breathing in mostly by swimming [but] also partly by buccal [gill] pumping. The 6th megamouth shark survived under roped condition, and so I think the megamouth shark can survive for some period of time only by buccal pumping."

We'll continue to update this post with any details regarding the hold, so watch this space.  

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Top header image: Hiroyuki Arakawa/Facebook 

The spectacled (or Andean) bear – which turns out to be more common around Machu Picchu than previously believed – is the only South American bear, found in the ranges of the Andes from Venezuela in the north to Peru and Bolivia in the south. 

But the species isn't unique just for being the only bruin on a huge continent: it's also the sole remaining representative of a bear family that once encompassed some of the all-out most formidable mammals ever to exist. 

Tremarctine titans

We're talking about a corner of the ursine family tree called Tremarctinae: the "running bears" or "short-faced bears". Neither of those descriptors is altogether accurate, based as they are on what may be a shaky understanding of perhaps the best-known of the extinct tremarctine species: the giant short-faced bear, Arctodus simus, which thumped around North America from about 1.8 million years ago to 11,000 years ago.

A. simus without question ranks as one of the biggest terrestrial carnivores of all time, alongside its tremarctine relatives: the South American giant short-faced bear (Arctotherium angustidens) and the huge African short-faced bear (Agriotherium africanum).

A male North American giant may have tipped the scales at well more than a ton, towering 5.5 feet or more at the shoulder, and rearing imposingly on its hind legs to nearly ten feet tall. 

Arctotherium angustidens, the biggest of five Arctotherium species known from Pleistocene South America, may have been even larger: as much as 3,500 pounds!

The heft of these vanished relatives makes the spectacled bear look like a pipsqueak, although of course a 400-pound animal – the size of an especially large male Andean bear – is plenty big by modern standards.

A rough place to live

The giant short-faced bears of the Americas outsized any other carnivores of their time. North America in particular once hosted a pretty staggering roster of toothy beasts: in the words of biologist Valerius Geist, a "predator hellhole" greeted human beings as they crossed over to modern-day Alaska from Siberia. We're talking cheetahs and American lions (bigger than any modern big cats); the saber-toothed cat Smilodon and "scimitar-toothed" cat Homotherium; running hyenas and dire wolves. And let's not forget the grizzlies, gray wolves, wolverines and other survivors of the megafaunal extinctions that helped close the latest Ice Age. 

Standing head and shoulders above this roaring and snarling gaggle was A. simus. Its exact ecological role, though, has been the subject of much debate. In this respect it resembles another of prehistory's great monsters, good old Tyrannosaurus rex. Palaeontologists have long debated whether the "tyrant lizard" was a terrifyingly active predator or a (still admittedly terrifying) scavenger.

The same controversy exists for A. simus, with a third potential lifestyle thrown into the mix: the omnivorous route taken by all modern ursids save the polar bear. Some have suggested the giant short-faced bear was a fast-running predator of ungulates, although the widespread idea that the species had longer legs than other bears has been questioned in recent years. (Same goes for the "short" face, although tremarctine bears do have a broader mug than some of their modern cousins.)

Other scientists suspect A. simus was a carrion-eater, and perhaps functioned as a kleptoparasite. They see the bear using its towering height (and sense of smell) to detect carcasses, its dogged pace to reach them, and its colossal size to send packing whatever brought down the meat in the first place – lion, saber-tooth, wolf and the like. 

Though the classic image of the beast places it on the Ice Age "mammoth steppe", we now know the bear ranged into what's now the southeastern United States, including present-day Florida, where it rubbed shoulders with tremarctine cousins like the Florida spectacled (or cave) bear. That means the titanic creature haunted not just open subarctic grasslands but also woodlands and forests. In such environments, the bear may have happily included plant food on its menu in addition to meat.

A 2010 journal article suggests omnivory as the sturdiest interpretation of the giants' dietary ways, but it also notes that short-faced bears of northern tundra and grasslands may well have been mainly meat-eaters – and with their scavenging tendencies, they might have benefitted from sharing the landscape with saber-toothed cats. Over-the-top fangs and a relatively weak bite likely made the bulky saber-tooth quite a specialised feeder, adapted for slicing flesh rather than chomping and crushing. That means the cat probably left behind ample meat and all the marrow-rich bone on its kills, providing plenty of spoils for the more powerful jaws of the short-faced bear.

It seems safe to conclude that the giant short-faced bear was, at the very least, a figure held in healthy respect by North America's colonising human beings – and quite possibly the most intimidating beast they had to contend with. It's even been suggested that bears and other formidable New World carnivores such as the American lion may have stalled or rerouted human expansion into the continent.

Naturalist and grizzly-bear expert Doug Peacock points out another possible legacy of North America's crowded Pleistocene predator roster. The grizzly bear (Ursus arctos horribilis), a subspecies of the brown bear, is generally a more aggressive and hot-tempered bruin than its Eurasian relatives – and some speculate that disposition has to do with coming of evolutionary age on the Ice Age steppes of North America.

In the wide-open barrens of those fraught times, a mother grizzly had to defend her cubs from lions, wolves, sabertooths and, yes, short-faced bears. The result? Possibly a more irascible version of the brown bear.

"It might be informative to examine the possibility that Pleistocene North America might have been an unusually rough place to live," Peacock writes. 

Sole survivor 

Easily romanticised and unquestionably impressive, the giant short-faced bears are plenty dramatic. But that shouldn't take anything away from the spectacled bear's own charms.

This most arboreal and herbivorous of bears inhabits a remarkable spread of habitats on the shoulders of the Andes, from the coastal desert of Peru to the cool páramo grasslands above the timberline. We're talking better than 14,000 feet of elevational range for the species.

Its quintessential habitat is the cloud forest, that moss-cloaked high jungle that reaches its zenith along the eastern slope of the Cordillera Oriental, between about 3,000 and 9,000 feet. 

A bit like South America's version of a great ape, the roughly gorilla-sized bear splits its time (gorilla-like) between forest floor and canopy, pulling itself up tree trunks and thick lianas. Mostly a plant-eater, it has a love for fruit, smashing down ripe branches too flimsy to support its weight.

When soft, juicy fruit isn't available, spectacled bears employ massive jaw muscles – rivalled among bears only by the giant panda – to munch tougher, more fibrous greenery. They've also got a strong taste for bromeliads: one local name for the creature, oco achupayero, means "bromeliad-eating bear".

But like all bears, this one won't turn up its stubby nose at animal protein. Insects, small mammals, carrion, even the occasional meat on the hoof – cows grazing on mountain pastures, for instance.

That taste for livestock sometimes brings the bears into conflict with human neighbours (as does their occasional fondness for munching corn and other cultivated crops).

Mitigating such conflict with people is essential for the conservation of the species, especially since the impacts of climate change on bear habitat and food sources appear to be heightening bear-human tensions in some areas.

In the interest of the carnivores and local livelihoods alike, one Bolivian biologist, Ximena Velez-Liendo, is helming a project aimed at reducing cattle losses to bears. Her initiative was recently announced as a finalist for a Whitley Award, the so-called "Green Oscars" that help fund conservation projects in the developing world.

Protecting the spectacled bear is important work, not least because of its ecological significance. "The spectacled bear is well-qualified to serve as an umbrella species for biodiversity in the Andes and in the world," explains biologist Bernard Peyton, noting how many endemic organisms fall within the bear's range. Safeguarding the future of the species in the Andes, therefore, helps to preserve whole ecosystems of outstanding biodiversity.

So we've got plenty of reasons to care about the spectacled bear: its own intrinsic worth (same as any creature) and the wide-ranging habitats it knits together in its foraging. And, lest we forget, the fact that this placid plant-eater is the only living link we have to a very grand pantheon: the mighty short-faced bears of yore, vanished titans that – like T. rex – can still evoke not a little fearful awe in our imaginations. 

Staff at Hillswick Wildlife Sanctuary (HWS) managed to film the whale floating near the foot of steep cliffs at Fethaland, which lies at the north tip of Shetland's mainland. 

"The Scottish Marine Stranding-Scheme team had sent out an alert, and we volunteered to go take photos for their database," they explain. "The huge male whale was decomposing and smelly, though this didn't seem to be putting off the gulls who were feeding on its remains."

This is a very remote corner of the islands, and much of the coastline is bordered by towering sea stacks. These vertical rock columns are formed by wave erosion, making them jagged and tricky to traverse. "There was no chance of taking samples as there was no route down the 40-metre-high cliff," says the team.

It's disappointing, no doubt – necropsies performed on dead whales can give us useful intel about their lives. 

Only a small number of whales that die at sea make it to shore; most descend to Davy Jones's locker long before scientists can get their hands on them. For a whale to hit land, for example, it has to expire close enough to shore (typically less than ten miles) to drift inland while its bloated body can still float. Factor in currents and offshore storms, and it's pretty incredible that we ever bump into these giant carcasses.

The state of this particular whale suggests it had been dead for some time. Several online commenters have speculated that the animal was an albino, but the depigmentation you see in the video is the result of normal decomposition, not a genetic mutation. Without access to those disintegrating tissues, it's impossible to accurately determine cause of death – but the body showed no obvious signs of ship strike or major injury. 

"It's unlikely to be going anywhere," says the team. "This was a sad and sorry end for such a magnificent creature, who will now provide food for many sea creatures over the next few weeks and months."

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Top header image: Roberto Saltori/Flickr

In a fjord system of northern British Columbia, Canada’s westernmost province, a team of scientists, non-profits and an indigenous monitoring group have uncovered a curious humpback whale behaviour. Dubbed the “whale wave”, it suggests local displacement of the animals caused by humans may have more consequences than previously thought.

By “wave”, researchers mean a seasonal shift in the habitats used by humpbacks. In the early summer, the whales concentrate in the outer channels of the fjord system nearest the open ocean. And, as the summer turns to autumn, they propagate further into the fjord system and deeper into the mainland.

More than ten years of whale surveys indicate that this complex pattern occurs at roughly the same time every year.

A wave that had gone undetected

Though annually persistent and remarkably specific in structure, the whale wave is not the kind of pattern that is picked up in typical marine mammal surveys. That’s because such surveys usually spread their precious time over a broad area.

In fact, the wave had gone undetected by several research groups in recent years, and it was only revealed thanks to more than a decade of annual local monitoring by the Gitga’at First Nation’s Guardian Team and their partners, the North Coast Cetacean Society (NCCS).

The thousands of survey hours these two groups logged in all months of the year allowed them to detect this curious pattern. And their deep familiarity with the study area, born naturally from living in it year-round, allowed them to interpret it and work with scientists from Scripps Institution of Oceanography and NOAA-NMFS Southwest Fisheries Science Center to develop a new study to understand drivers of the wave.

The wave’s discovery was recently published in a top-tier marine ecology journal. It included the work I conducted with a small team of students to better understand the drivers of this strange humpback behaviour.

We worked with the Gitga’at and NCCS to develop a hypothesis-driven ecosystem study of fjord habitat and the ways humpbacks are using it. Mirroring the patient watchful approach of the Gitga’at and NCCS, we lived and studied from a research sailboat for the 2015 feeding season, from May through September.

Increased large ship traffic

It all happened in the Douglas Channel fjord system, a beautiful and remote network of steep-walled corridors once known for its remote beauty and mysterious “spirit” bears (white morphs of the black bear).

Today, Douglas Channel is better known for the slew of oil and natural gas tanker routes proposed for its winding waterways. Of the proposed tanker projects, the Enbridge Northern Gateway Pipeline was most contentious due to its crude bitumen cargo and associated risk of disastrous spills.

But from a whale’s perspective, the spills are not the only concern. Fatal ship strikes, injury or starvation due to entanglement in debris, and disorientation and disturbance due to ship noise are some of the most probable of many potential consequences of increased large ship traffic within these confined waters.

Since the Northern Gateway was finally shut down last northern autumn after the Gitga’at and other coastal First Nations won a prolonged legal battle, attention has shifted to the several liquified natural gas (LNG) pipeline and tanker proposals slated for the port of Kitimat at the head of Douglas Channel.

The proposed tanker routes divide the Douglas Channel fjord system fairly neatly in two. Every summer, the whale wave passes up from the fjord’s outer channels to its innermost waters, overlapping with different portions of the proposed tanker routes as it goes.

A critical habitat

The humpback whale, loved worldwide for its complex song, picturesque flukes and fantastic aerial behaviours, is the most abundant baleen whale in British Columbia waters.

The Douglas Channel area has been proposed as a “critical habitat” for the feeding opportunities it provides British Columbia’s humpback whales. Several hundred individuals are considered “resident” to its confined waters. And this number is growing every year according to Janie Wray, lead researcher for the North Coast Cetacean Society, who has been studying the whales since 2003.

Humpback whales are not the only cetaceans to rely upon the Douglas Channel fjord system. The area was proposed as critical habitat for Northern Resident and Bigg’s (transient) killer whales, and is being evaluated as a potential critical habitat for fin whales, the second-largest species in earth’s history.

Specific behaviours

Some results of our study were unexpected. We were surprised to find, for instance, that the monthly distribution of prey was a poor predictor of the whale wave.

“Our findings suggest humpback foraging needs within this fjord system are balanced against needs other than food and that the balance shifts through the year,” noted Janie Wray of NCCS.

Other factors that may be in play include physical and social habitat needs such as the water’s depth and the acoustic properties of the fjords for communication and singing, as well as companionship for the purpose of travelling within a group or mating.

Our findings suggest that this wave likely results from humpbacks familiarising themselves with this critical habitat over many years and developing specific behaviours coordinated to the specific oceanography of the fjord system that enable them to make the greatest use of its resources.

We realised that this meant local displacement of whales by human impacts may have more consequences than previously supposed. We can’t expect these whales to simply pick up and go somewhere else if industrial activities, such as shipping lanes, disrupt continuity of critical habitats, such as the Douglas Channel fjord system.

Until thorough habitat-use studies are completed, irrevocable management decisions should be treated with caution.

Whales and their habitat

“This study shows just how intricate the relationship between humpback whales and their habitat is, and it raises important questions about their conservation,” said Arnold Clifton, chief councilor and hereditary chief of the Gitga’at First Nation. “In light of the industrial pressures facing our territory, our Nation’s reliance on the sea and the sensitivity and complexity of the area’s ecology, our leadership’s commitment to conservation and long-term local monitoring by our Gitga’at Guardians has never been more important or stronger.”

The whale wave is a perfect example of the conservation value of small, long-term research partnerships of neighbours, which is a model that the Save Our Seas Foundation, a supporter of NCCS, has applied to protecting ocean species worldwide.

In the cetology classic "Among Whales", Roger Payne wrote that “[A]ny observant local knows more than any visiting scientist. Always. No exceptions.”

What other intricate patterns in the sea could be going unnoticed by visiting scientists on their chartered vessels? Perhaps there are some discoveries that reveal themselves only to those who are residents first, and scientists second.

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Top header image: Brian Digital/Flickr

Eric Keen, Ph.D. candidate, Biological Oceanography, Scripps Institution of Oceanography, University of California, San Diego

This article was originally published on The Conversation. Read the original article.

True to its name, the most common footprints at the site belong to meat-eating theropod dinosaurs that walked across this part of the world in the Early Jurassic, more than 175 million years ago. The largest of these, a type of footprint named Eubrontes (yes, footprints get their own genus and species names!), are as big as 40 centimetres (16 inches) long.

On the other end of the spectrum are diminutive tracks called Anomoepus, less than three centimetres (one inch) long, belonging to very small dinosaurs. Whether these came from a pint-sized species or younglings is uncertain, but the fact that many of these trackways occur together suggests these little dinos may have been gathering in groups.

"The Gary Gaulin site appears, at first glance, to be completely unimpressive," says Patrick Getty of the University of Connecticut, referring to the site's small area. "What makes it impressive is the types and quality of fossils that are being collected there."

Getty spoke about his own work on the site, and that of his colleagues, during the Triassic-Jurassic Research Symposium last week at the Bruce Museum in Connecticut.

The site, located in what is the city of Holyoke today, was once an ancient playa lake – a shallow, dry-climate body of water that fills in and dries out as the seasons pass.

The preserved ripple marks in the rocks are evidence of the lake's shallow waters, and a series of petrified mudcracks reveal a history of successive wetting and drying. Dinosaurs likely visited this body of water each year, leaving the footprints that are now entombed in multiple stacked layers of mudstone and sandstone.

Once you look past the eye-catching dinosaur prints, traces of much smaller prehistoric track-makers come into view. Tiny grooves running across the rock reveal the presence of long-gone arthropods that walked (or swam) by. The site is also pockmarked with the burrows of worms and insects that made their homes just beneath the lakebed. There's even the body imprint of a creepy-crawly that stopped for a moment to rest in the mud. 

But perhaps the most surprising "footprints" at the site weren't left by feet at all, but by fins! S-shaped trails called Undichnus represent the sweeping tails of fish as they swam though the shallow waters during the wet seasons.

"The fish trails ... are important because they support the idea that the carnivorous dinosaurs in the valley ate fish," Getty explains.

Tracks of meat-eating dinosaurs are extremely common at the site, but herbivores are much rarer, which left researchers wondering what sort of creatures were once at bottom of the food chain here. "This helps to makes sense of what is a very weird ecological conundrum."

The northeast United States is actually famous for its many fantastic tracksites, formed at a time when the supercontinent Pangaea was breaking apart.

"As the landmass fragmented, huge valleys opened up [and] filled with lakes that had muddy and sandy margins that were conducive for footprint production and preservation," Getty explains. "A similar process is occurring today in the horn of Africa, which is pulling away from the rest of the African continent."

The Gaulin tracksite first appeared on Getty's radar during his university days, but even years later, he suspects the site has not yet run out of surprises. "I think it's got a potential for quite a bit more very exciting discoveries over the next couple of years."

The good news first: the formerly resident reptile, a male nicknamed "Cleatus", is still rocking and rolling, but he's now doing it on the brackish fringe of the Everglades, more than a hundred miles northeast from the island haven he'd called home for more than a decade.

The managers of Dry Tortugas National Park – among the most geographically isolated parks in the United States – decided to remove the roughly nine-foot-long American crocodile from his chosen abode on Garden Key due to safety concerns. The reptile had lately begun showing signs of unhealthy habituation to people, apparently due to anglers and other park visitors feeding him.

Cleatus first appeared in the Dry Tortugas in 2003, specifically on the chain's easternmost islet, East Key. Soon enough he'd pulled up stakes and moved westward. According to the National Park Service, he'd spent most of his tenancy in little-visited haunts of Garden and Bush keys, but more recently he was frequenting some of the park's popular visitor areas on the former islet.

These included Garden Key's campground, swimming areas and the moat edging Fort Jefferson, a mighty brickwork fortress built in the mid-1800s. (You have to admit: a crocodile prowling the moat of a castle-like stronghold is pretty much perfect.)

His new hangouts brought him into closer proximity to tourists, who unfortunately didn't help matters by tempting the croc with food. For the most part, American crocodiles are far shier around people than some of their Old World relatives (though they've earned something of a bad reputation in Costa Rica, and a Florida croc once demonstrated – in non-fatal fashion – the perils of going night swimming at South Miami house parties). But be it ground squirrel or living dinosaur, any animal accustomed to getting snacks from people may become aggressive.

"We were starting to see a strong connection between people and food for the croc," Glenn Simpson, manager of Dry Tortugas National Park, told the Miami Herald. "It would start following people. When we start to see a chance in behaviour like that, it's an indicator that the risk is a lot higher."

The final straw came recently when an angler tried to draw the crocodile closer with chum – and Cleatus enthusiastically complied.

This is why, on May 14, the Dry Tortugas croc found himself lassoed from his moat, muzzled with tape, hauled by a squad of bipeds into a plane and flown across the glittering waters of the Gulf of Mexico to more typical digs for his kind: the mangrove lagoon of West Lake in Everglades National Park.

Cleatus's arrival in the Dry Tortugas in the early aughts was a novelty. Closer to Cuba than the Florida mainland, this faraway sprinkle of seven sandy keys atop a coral bulwark – named by the Spaniards in the 1500s for sea turtles (tortugas) and a lack of freshwater – wasn't really thought of as croc country.

Florida marks a northern frontier for the basically tropical American crocodile, which may reach 20 feet. That was likely true even before human persecution and habitat loss starting contracting the croc's turf everywhere: unlike the subtropical American alligator, which overlaps with its toothier relative in South Florida, the American croc can't withstand cold temperatures. 

Down to a few hundred individuals in the 1970s, Florida crocodiles have rebounded to some 2,000 thanks to stringent conservation measures. Their stronghold is the South Florida mainland's Greater Everglades coast, where they inhabit mangrove backwaters and canals, as well as the islets of Florida Bay and the Upper (aka eastern) Florida Keys. 

Some evidence suggests the small croc population in the Lower Keys is growing, perhaps breeding. But a 70-mile span of open sea separates Key West and the stubbornly remote Dry Tortugas. 

A Roads & Kingdoms profile of Cleatus by Mark Hedden noted that while a DNA sample taken from the beast in 2008 revealed a Greater Everglades origin for his mother, his father might have been a Jamaican croc. In other words, Hedden wrote, "the father may have been from Jamaica (but [scientists] can't say for sure), may have swum around Cuba to get laid (but they can't say for sure), and that papa, like his son, may have been a bit of a rolling stone."

A diver bumps into Cleatus back in 2014.

Son Cleatus chanced quite the high-seas crossing to reach the Dry Tortugas from the Everglades coast or the Lower Keys, whether he made the swim unaided or surfed over on hurricane swells (as some have suggested).

The feat is impressive, but not out of character for the species: like its relative the Indo-Pacific croc, the American croc isn't at all opposed to stints in saltwater. It's mostly a coastal animal, formerly cruising much of the Caribbean, and known from tropical isles and atolls on both the Pacific and Atlantic coasts. Itinerant crocs have showed up significantly outside their traditional geography, including South Carolina beaches.

Maybe more surprising than Cleatus's voyage was his decision to stick around the Dry Tortugas despite the distinct lack of scaly compadres. Some called him "the world's loneliest crocodile", though of course we can't say whether or not Cleatus might have relished his solitude.

It'll be interesting to see how the Dry Tortugas croc adjusts to life in West Lake, sharing quarters with others of his kind (plus alligators). Territorial disputes and perhaps romantic passion of the sort he hasn't known for at least 14 years may be in the offing. 

It's worth noting that translocated crocodiles have a habit of ditching their new quarters and hightailing it for former haunts. That said, odds are Cleatus won't be able to repeat his voyage to the distant hinterland of the Florida Keys. 

Everglades National Park staff, meanwhile, will be able to keep tabs on the croc thanks to the numbered yellow tag he now sports. 

Cleatus's laidback solitary presence in the Dry Tortugas will surely be missed. As Glenn Simpson told The Miami Herald, "It's unfortunate. We would have loved to keep him here forever."

But even if Cleatus doesn't do it himself, who's to say another croc – one not afraid of big ocean horizons – might not someday take up residence in his old HQ?

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Top header image: Sebastián Restrepo Calle/Flickr

Despite her rather uninventive name, Grizzly Bear 399 – or 399 for short – is one remarkably popular bruin. This native of the Greater Yellowstone Ecosystem has her own Twitter account and Facebook page, and her calm demeanour and peaceful interactions with humans have earned her a big fan base over the years. So when 399 disappeared after losing her white-faced cub, Snowy, to a hit-and-run motorist in 2016, fans were worried about her fate.

Now, those fears have been put to rest: a sighting of 399 in Grand Teton National Park earlier this week proves she's not only alive and well, but also seems to be thriving for a bear of her years. At the venerable age of 21, she's far beyond the usual age that most female bears would mate. And yet, the bear mama was filmed in the same area where she lost Snowy with two spry cubs bounding after her.

According to National Park Service bear management specialist Kate Wilmot, who was lucky enough to witness 399's road-crossing, the mama bear appeared healthy, and judging by their small size, her cubs looked to be around three months old. 

"They were just walking," Wilmot told Jackson Hole News & Guide. "They were close to the road but then they disappeared quickly."

Social media fans weren't the only ones excited by the bear's return to the public eye. Watching footage of the bear family was an emotional experience for Thomas Mangelsen, a wildlife photographer who has spent a decade documenting 399.

"I had a hunch she would show up one more time, but in nature there are no guarantees, and it's not easy being a grizzly in the modern world," Mangelsen told National Geographic. "Every year that 399 has remained alive, raising successive broods of cubs, staying out of trouble with people, has been for those of us who enjoy her presence a gift and a miracle. After Snowy's death we prayed she might make an encore."

Mangelsen isn't exaggerating the grizzly's woes in the modern world. A staggering 85% of grizzly deaths in the Greater Yellowstone Ecosystem can be tied to human activity, according to National Geographic. And although numbers have recovered somewhat since the subspecies received protection under the US Endangered Species Act more than four decades ago, the looming threat of delisting now has some conservationists worried about their future.

Popular bears like 399, who are used to seeing tourists on their roadside ambles, offer the public a unique opportunity to appreciate wildlife, and are important for good human-bear relations – but such encounters also need to be handled responsibly, caution park officials. That means observing park speed limits and keeping a respectful distance (at least 100 yards) away from the bears.

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Top header image: Pat Gaines/Flick

Exactly why the tiger – nicknamed Vladik by locals – prowled into the city in the first place remains a mystery. At the time, conservationists speculated that the young male may have been searching for his own territory after leaving his mother. Once inside the urban jungle, the big cat may have struggled to find his way back out, with multiple highways blocking escape. 

After finally being tracked down on the side of a road outside of Vladivostok, the starving cat was slowly nursed back to health by the Amur Tiger Centre.

"Vladik is a mysterious tiger," Sergey Aramilev, the centre's Far East Director, told the Siberian Times. "We don't know how he ended up in Vladivostok." 

Aramilev is much less ambiguous about his organisation's decision to release the tiger into Russia's newly formed Bikin National Park, a location far from the wilderness around Vladivostok.

"As we know, male tigers can travel huge distances," he said. "That's why, given his past and passion for city life, we decided to take him to the most remote area of wild taiga with a big number of hoofed ungulates as a food supply."

The striped predator's relocation to the remote national park was undoubtedly welcome news for city residents, but it was also a great relief to conservationists that the cat survived his brush with urbanisation.

Siberian tigers – also known as Amur tigers – are listed as Endangered on the IUCN Red List, and were considered Critically Endangered as recently as 2007. Although the subspecies has recovered significantly from its population nadir of 20 to 30 animals in the 1930s, numbers are still very low: at most, only 540 of these cats are thought to be living in the wild. Of those 540 animals, the majority lives in the region surrounding Vladivostok, with only a handful across the border in China.

While a roaming Siberian tiger like Vladik can pose a danger to humans, the threat is far greater in reverse: through habitat destruction and hunting, humans have been the main cause behind the decline of tigers across the globe. According to the World Wildlife Fund (WWF), we've lost over 96% of wild tigers in the last century.

After bringing Vladik back from the brink of death, the Amur Tiger Centre wanted to ensure this young male had a role to play in the preservation of his subspecies. The release location was strategic: conservationists, Aramilev included, are hopeful that tigers like Vladik will remain in habitats isolated from humans and get on with the important business of reproducing, in this way progressing the species on the long trek back from the brink of extinction. Vladik was tagged with a GPS collar before release so that his journey can be tracked.

"I hope he'll stay there, won't go too far and will increase the number of tigers in [the] Bikin National Reserve," Aramilev said. The WWF, a partner to the Amur Tiger Centre, echoes his sentiments, telling the Associated Press that the team is confident Vladik "has little chance of wandering into urban jungles again".

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Top image: Brocken Inaglory/Wikimedia Commons

The footage was filmed recently by dolphin conservationist Jenni Wyrsta during a trip off the coast of Adelaide. What makes her video so interesting is that the Port River dolphins haven't performed their signature trick (at least in front of people) since 2009, when a renowned tail-walking dolphin known as "Billie" died.

"It was a truly spectacular day," Wyrsta says. "Some of them [did] doubles! I have never, ever seen that." Over the course of the trip, at least four dolphins took to their tails, with some hitting dozens of walks in front of human onlookers. 

Dr Mike Bossley, who has studied the Port River dolphins for more than 30 years, was also surprised to see this in action once again. 

"One of these tail walkers is the young adult female Oriana, and Oriana's mother is Bianca, who is also a tail walker,” he told Adelaide Now. In fact, every individual seen resurrecting the move had parents who'd also mastered it. This suggests we're looking at an example of animals "culturally transmitting" a playful behaviour.

The Port River pod's origin story is a bit hazy, but local scientists trace their tail walking back to Billie, who did a one-month rehabilitation stint at a marine park in the 1980s. During that time, Billie was housed with several captive dolphins who had been trained to walk on their tails.

After being released, Billie may have brought the trick back with her, and other pod members simply followed her lead. It's possible that this could spawn generations of new tail walkers over time – all of them learning the behaviour by mimicking their mothers.

Many youngsters learn to forage and protect themselves in the same way, but it's rare for a species to "teach" behaviours that have nothing to do with such crucial skills.

We don't know what sparked this latest "walk off", but Wystra notes that the pod has been especially social recently. She speculates this could have something to do with an abundance of food in the area. Just like with many other species, dolphins tend to exhibit more play behaviour when the going is easy. 

That's just a hunch, but since we have yet to discover any practical use or benefit to tail walking, our best guess is that this pod is simply having fun.

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Top header image: Richard Herbert/Flickr