Kukri snakes cut frogs and frogs before inserting their heads into their bodies and eating their organs one by one while the prey is still alive, scientists report.
Biologists have published three studies, each detailing the horrible feeding behavior of one of three different species of kukri snakes in Asia.
The three closely related species of snakes, all within the genus Oligodon, keep the prey alive for “up to a few hours,” according to the study’s authors.
The footage below shows one – the Taiwanese kukri snake (Oligodon formosanus) – with its head buried deep in the abdomen of the bullfrog (Kaloula pulchra).
In the bloody attacks seen in the jungle, the frogs struggled vigorously to escape and “avoid being eviscerated alive” – but their efforts were in vain.
The attacks can last for a few hours, depending on which organs the snake pulls out first.
An ocelated kukri snake (Vietnam) first pierced this poisonous common Asian frog and buried its head deep in the amphibian’s abdomen, as it was probably eating the organs. However, as can be seen in the photo, the kukri snake started to swallow the entire frog
The footage also shows the relentless snake repeatedly rotating its body longitudinally in an elaborate performance known as the ‘death roll’.
“We believe that the purpose of these death lists was to uproot organs for later swallowing,” said study author Henrik Bringsøe, a herpetologist in Køge, Denmark.
Two of the three articles describing the horrible behavior, all by Bringsøe, were published this month.
One reports the horrible feeding strategy of the Taiwanese kukri snake (Oligodon formosanus) and the other, the same strategy of the ocelated kukri snake (Oligodon ocellatus).
The other article, published in September last year, describes the same behavior in the small-banded kukri snake (Oligodon fasciolatus).
The three species of snakes closely related within the genus Oligodon developed this unusual and distressing behavior.
Image of a footage of a Taiwanese kukri snake that opened the abdomen of a bullfrog (Kaloula pulchra) and extracted several organs that it is biting and chewing. The video shows the snake in the process of swallowing. The observation took place in Hong Kong. The complete footage of this meeting can be seen below
Interestingly, these species have also been registered to feed in a more conventional way – by swallowing their prey whole.
It is likely, therefore, that this alternative strategy has evolved to be able to eat much larger animals.
One of the new studies reports two cases in Hong Kong, where Taiwanese kukri snakes have been observed eviscerating bullfrogs with bands.
In one case, the snake cut off the frog’s belly and inserted its head into the frog’s abdomen, before repeatedly executing its deadly test.
In the other case, the frog’s organs were ripped from its abdomen.
The second recently published research article details the behavior of the ocelated kukri snake, which has been observed eating the toxic black-spotted Asian frog (Duttaphrynus melanostictus) in Vietnam.
The Asian spotted toad is known to secrete a potent toxin from the parotid glands in the neck – but this does not appear to have any lethal effects on the predator.
Initially, the snake was seen burying its large head eyes deep in the amphibian’s abdomen.
Ultimately, the snake swallowed the entire frog despite its toxicity, which shows that the kukri snakes are resistant to the cardiac glycosidic toxins of the frogs.
The less recent September newspaper marked the announcement of the eating habit – described as ‘never before seen on a snake’.
He described several examples of the small-banded kukri snake (Oligodon fasciolatus) feeding on the Asian frog with black spots.
At the time, the research team pointed out that smaller frogs of this species tended to be swallowed whole – possibly because they were less toxic than adults.
A small banded kukri snake with its head inserted into the right side of the abdomen of an Asian frog with black spots, in order to extract and eat the organs. Tissue from a collapsed lung (above left) and possibly adipose tissue, covered with a clear foaming liquid when it mixes with lung air bubbles on exhalation. The upper part of the front leg is covered with blood foam, similarly, mixed with air bubbles from the collapsed lung
In one of the new articles, Bringsøe and his team include new details of a new observation of the small-banded Kukri snake (Oligodon fasciolatus).
The team reveals that it prefers to swallow its prey whole after making the same ‘death test’.
This has led scientists to be more inclined to believe that it is the size of the prey that determines exactly how the snake would make its dinner.
“We hope that future observations will reveal additional aspects of the fascinating eating habits of kukri snakes, although we can call them horrible,” said Bringsøe.
All research articles are published in the magazine Herpetozoa, peer-reviewed.