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 say.
Biologists have published three studies, each detailing the feeding behavior of feeding on one of three different species of kukri snakes in Asia.
The three closely related species of snakes, all of the genus Oligodon, keep prey alive “for up to a few hours,” according to the study’s authors.
The images below show one – the Taiwanese kukri snake (Oligodon formosanus) – with its head buried deep in the abdomen of the banded bull frog (Kaloula pulchra).
In the bloody attacks seen in the wild, heavy frogs struggled to escape and “avoid being gutted alive” – but their efforts were in vain.
The attacks can last up to a few hours, depending on the organs that the snake removes first.
An Ocellated 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 its organs. However, as seen in the photo, the kukri snake began to swallow the whole frog
The images also show the ruthless snake repeatedly rotating its longitudinal body, in an elaborate performance known as the “role of death”.
“We believe that the purpose of these death roles was to rupture the organs for later swallowing,” said study author Henrik Bringsøe, a herpetologist based in Køge, Denmark.
Two of the three works describing the horrific behavior, all written by Bringsøe, were published this month.
One reports the feeding strategy of the Taiwanese kukri snake (Oligodon formosanus), and the other the same strategy of the ocellated kukri snake (Oligodon ocellatus).
The other paper, published in September last year, describes the same behavior in the low-banded kukri snake (Oligodon fasciolatus).
The three closely related species of the genus Oligodon have developed this unusual and awful behavior.
Ever since the filming of a Taiwanese kukri snake that cut the abdomen of a banded bull frog (Kaloula pulchra) and extracted several organs that it bites and chews. The video shows the snake in the process of swallowing. The observation took place in Hong Kong. The full images of this meeting can be viewed below
Interestingly, these species have also been recorded to feed in a more conventional way – by swallowing whole prey.
Therefore, it is likely that this alternative strategy has evolved to be able to eat with much larger animals.
One of the new studies reports two cases in Hong Kong in which Taiwanese kukri snakes were spotted exposing bull frogs in the band.
In one case, the snake opened the frog’s belly and stuck its head in the frog’s abdomen before repeatedly performing the role of death.
In the other case, the frog’s organs had been forced out of the abdomen.
The second recently published research paper details the behavior of the ocellated kukri snake, which was observed eating the toxic black-spotted Asian frog (Duttaphrynus melanostictus) in Vietnam.
The black-spotted Asian frog is known to secrete a strong toxin from the parotid glands in its throat – but these do not appear to have any lethal effects on the predator.
Initially, it was seen that the snake buried its eyes with its big head, deep in the amphibian’s abdomen.
Eventually, however, the snake swallowed the whole frog despite its toxicity, providing evidence that kukri snakes are resistant to the cardiac glycosidic toxins of frogs.
The less recent newspaper in September marked the announcement of the habit of eating – described as “I have never witnessed a snake”.
He described several cases of the low-banded kukri snake (Oligodon fasciolatus) feeding on the black-spotted Asian frog.
At the time, the research team pointed out that smaller frogs of this species tended to be swallowed whole – possibly because they are less toxic than adults.
A small-banded kukri snake, with its head inserted through the right abdomen of a black-spotted Asian frog, to extract and eat the organs. Tissue of a collapsed lung (above, left) and possibly adipose tissue, covered with clear liquid foam, while mixing with air bubbles from the lungs on expiration. The upper leg is covered with foaming blood, similarly mixed with air bubbles from the collapsed lung.
In one of the new works, Bringsøe and his team include new details about a new observation of the low-banded Kukri snake (Oligodon fasciolatus).
The team reveals that they prefer to swallow their entire prey after making the same “death”.
This has led scientists to be more inclined to believe that the size of the prey determines exactly how the snake would be at dinner.
“We hope that future observations may reveal additional aspects of the fascinating feeding habits of kukri snakes, although we can call them really awful,” Bringsøe said.
All research papers are published in the open access journal Herpetozoa, reviewed by colleagues.