African toad pretends to be a snake


This 21 October 2019 video says about itself:

It is well known that some harmless animals mimic dangerous animals to ward off predators.

Eg, the Brazilian galliwasp lizard poses like a toxic millipede. And the zebra shark can mimic a highly poisonous banded sea snake.

Such posing is called Batesian mimicry. But the Congolese giant toad takes Batesian mimicry to a new level. According to a paper in the Journal of Natural History, the toad not only transform into a very good copy of a Gaboon Viper. It also tries to mimic the hiss the deadly snake make before an attack. The toad also postures so that its front limbs aren’t visible — making it look more snake-like. The Congolese giant toad are found in locations inhabited by the Gaboon viper. The Gaboon viper has the longest fangs and carries the most venom.

From ScienceDaily:

Toad disguises itself as deadly viper to avoid attack

Decades of fieldwork uncover hissing and strike-warning impersonations by toad

October 21, 2019

The first study of a toad mimicking a venomous snake reveals that it likely imitates one of Africa’s largest vipers in both appearance and behaviour, according to results published in the Journal of Natural History.

The Congolese giant toad, a triple cheeseburger-sized prize for any predator, may use its ability to mimic the highly venomous Gaboon viper to escape being eaten. The viper has the longest snake fangs in the world and produces more venom than any other snake.

“Our study is based on ten years of fieldwork and on direct observation by researchers lucky enough to see the toad’s behaviour first-hand. We’re convinced that this is an example of Batesian mimicry, where a harmless species avoids predators by pretending to be a dangerous or toxic one,” says Dr Eli Greenbaum from the University of Texas at El Paso. “To fully test our hypothesis, we’d have to demonstrate that predators are successfully duped, but this would be very difficult in the wild, where the toads are only encountered rarely. However, based on multiple sources of evidence provided in our study, we are confident that our mimicry hypothesis is well-supported.”

The researchers made comparisons between the appearance of the toad, found in central African rainforests, and the viper, which is more widespread in central, eastern and southern Africa. Using live wild-caught and captive specimens, as well as preserved museum ones, they found that the colour pattern and shape of the toad’s body is similar to that of the viper’s head. Most striking are two dark brown spots and a dark brown stripe that extends down the toad’s back, the triangular shape of the body, a sharp demarcation between the tan back and dark brown flanks, and the species’ extraordinarily smooth skin for a toad. Because the Gaboon viper is capable of causing deadly bites, would-be predators likely avoid the similar-looking toads to ensure they don’t make a lethal mistake.

Some mimics are exclusively visual, but for the Congolese giant toad, getting the look right is only part of the impersonation. If a Gaboon viper feels threatened, it will often incline its head and emit a long, loud warning hiss before it actually makes a strike. Similarly, Congolese herpetologist Chifundera Kusamba observed the toad emitting a hissing noise resembling the sound of air being slowly released from a balloon. Over a century ago, American biologist James Chapin observed a bow display by the toad, where the front limbs no longer prop up the viperine-shaped body, which looks similar to the cocked head of a snake threatening to strike.

The final part of the impersonation is getting the location right. Even the best impression will only work if predators of the harmless species are familiar with the venomous one. The researchers compared the geographical range of the toad and viper in the Democratic Republic of Congo (DRC) and found that the Congolese giant toad does not seem to occur in areas where the Gaboon viper is absent. The researchers identified 11 locations in the eastern rainforests where the range of both species overlaps.

Based on speciation dating estimates from genetic data, the Congolese giant toad and Gaboon viper first evolved at about the same time in the early Pliocene about 4-5 million years ago. Considered with their similar appearance, behaviour, and overlapping geographic distribution, the toads and vipers likely coevolved together, further supporting the mimicry hypothesis.

“Given the relatively large size and therefore calorific value of this toad compared to other species, it would make tempting prey to a large variety of generalist predators, including primates and other mammals, lizards, snakes and birds,” says Kusamba, from the Centre de Recherche en Sciences Naturelles, DRC. “Many of these predators use vision to find their prey, and because the viper is deadly venomous, they probably recognise the distinctive, contrasting markings from a considerable distance and avoid the toad because of them, receiving a threatening hiss if the appearance doesn’t put them off.”

Perhaps the best-known examples of Batesian mimicry are in butterflies, where around a quarter of over 200 Papilio swallowtail butterfly species are non-toxic impersonators of toxic ones. Other examples from the animal kingdom include comet fish that fool predators into thinking their tail is a moray eel‘s head, the Brazilian galliwasp lizard that mimics a toxic millipede, and zebra sharks that take on the coloration and undulating movements of venomous sea snakes. Many harmless snakes mimic venomous ones, and some caterpillars, legless lizards, and even birds are able to do so. However, the current study is the first to identify an amphibian mimicking a venomous snake.

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Snakes in Uganda, video


This 2019 video says about itself:

In a new documentary by Living Zoology film studio, you will see fascinating footage of venomous snakes and know more about the export of snakes from Africa. Matej Dolinay and his wife Zuzana Dolinay visited Uganda in the quest to find some of the most beautiful venomous snakes in the world – Gaboon vipers, rhinoceros vipers, bush vipers (Atheris squamigera and Atheris hispida), Jameson’s mambas and forest cobras. They also found the hybrid between Gaboon and rhinoceros viper – gabino viper.

Top Ten of most beautiful snakes


This 2017 video says about itself:

10 Most Beautiful Snakes In The World

When it comes to snakes, most people would actually think of scary venomous animals. While some snakes are venomous, some are actually quite harmless to humans.

Despite their venomous / non-venomous properties, some snakes are actually really beautiful. In this video, we are going to look at 10 most beautiful / pretty / prettiest / gorgeous / wonderful looking snake species in the world.

These snake species include Asian vine snake, blue racer, eastern coral snake, green tree python, iridescent shieldtail, red-headed krait, Formosan odd-scaled snake, Honduran milk snake, Brazilian rainbow boa and San Francisco garter snake.

New snake species discovery in Eurasia


An individual of the new rat sake species, Elaphe urartica, from Armenia. Credit: Boris Tuniyev

From PeerJ:

New snake species in Europe named after a long-forgotten Iron Age kingdom

May 28, 2019

An international team of scientists identified the snake and its range, which includes Turkey, Azerbaijan, Armenia, Georgia, Iraq, Iran, and Russia including a small region extending into the corner of Europe. Based on the genetic and morphological data, the researchers were able to say that the Blotched Rat Snake (Elaphe sauromates) actually comprises two different species and includes a cryptic species — dubbed Elaphe urartica — that has been named after the old kingdom of Urartu.

The kingdom, forgotten for over a thousand years, flourished between the 9th and 6th centuries BCE in the region of today’s Armenian Highlands, centered around Lake Van in Turkey, where this new snake species occurs. The name was chosen out of respect for the original scientific name of the Blotched Rat Snake proposed by the famous Prussian natural historian of the 19th century, Peter Simon Pallas.

The name Elaphe sauromates refers to Sarmatians, a confederation of nomadic peoples who inhabited vast areas of the recent range of the Blotched Rat Snake between the 5th century BCE and 4th century CE. According to Daniel Jablonski and David Jandzik, lead scientists of the project from the Comenius University in Bratislava, Slovakia, these snakes are very rarely observed in the field and are mostly distributed in geopolitically complicated regions. As a result, the material for their study was collected for over 17 years and required a broad international collaboration.

The new snake species is a member of large-bodied snakes of an iconic genus Elaphe, which is very popular with snake hobbyists. The discovery and analysis of the biogeographical history of this new snake fills in an important piece of the Eurasian biota evolutionary puzzle.

Sea snakes can dive deeply


This 2014 video says about itself:

In this exciting adventure, Jonathan travels to Manuk, a tiny, uninhabited volcanic island several hundred miles from the nearest populated island in Indonesia, on a mission to discover why the waters of this remote place are teeming with thousands of venomous sea snakes!

From the University of Adelaide in Australia:

Sea snakes make record-setting deep dives

April 2, 2019

Sea snakes, best known from shallow tropical waters, have been recorded swimming at 250 metres in the deep-sea ‘twilight zone‘, smashing the previous diving record of 133 metres held by sea snakes.

Footage of a sea snake swimming at 245 metres deep, and another sea snake at 239 metres has been provided to University of Adelaide researchers by INPEX Australia, an exploration and production company operating in the Browse Basin off the Kimberley coast of Australia. Both snakes appeared to belong to the same species.

Sea snakes are found in tropical waters of the Indian and Pacific Oceans and are typically associated with shallow water habitats like coral reefs and river estuaries.

“Sea snakes were thought to only dive between a maximum of 50 to 100 metres because they need to regularly swim to the sea surface to breathe air, so we were very surprised to find them so deep”, says Dr Jenna Crowe-Riddell, lead author of the study and recent PhD graduate at the University of Adelaide’s School of Biological Sciences.

Oceanic depths between 200 and 1000 metres encompass the mesopelagic zone, sometimes called the ‘twilight zone’ because only a small amount of light reaches that depth.

“We have known for a long time that sea snakes can cope with diving sickness known as ‘the bends’ using gas exchange through their skin,” says Dr Crowe-Riddell. “But I never suspected that this ability allows sea snakes to dive to deep-sea habitats.”

These record-setting dives raise new questions about the ecology and biology of sea snakes.

“In some of the footage the snake is looking for food by poking its head into burrows in the sandy sea floor, but we don’t know what type of fish they’re eating or how they sense them in the dark,” she says.

The snakes were filmed in 2014 and 2017 using a remotely operated vehicle or ‘ROV’ undertaking work for the INPEX-operated Ichthys LNG Project. …

Published in the journal Austral Ecology, the study is a collaboration between the University of Adelaide, the INPEX-operated Ichthys LNG Project, James Cook University in Australia, and The Royal Danish Academy of Fine Arts (KADK) in Denmark.

Kangaroo rats against rattlesnakes


This 26 March 2019 video says about itself:

Kangaroo rat defensive kicking of rattlesnake while jumping

High speed recording of a desert kangaroo rat (Dipodomys deserti) defensively kicking away a sidewinder rattlesnake (Crotalus cerastes) in mid-air. The animals are free-ranging in their natural desert habitat at night, and filmed with high speed cameras using near-IR lights invisible to both species. The video is recorded at 500 frames per second, and playback is slowed down about 30 times. This clip shows the ability of kangaroo rats to avoid venom injection even when bitten by using a forceful mid-air kick to dislodge the snake and push it away. Scientific details of this study are published in Freymiller et al (2019, doi 10.1093/biolinnean/blz027). Find more information and additional bonus videos here.

See also here.