Kukri snakes cut frogs and frogs open before sticking 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 outlining the horrific feeding behavior of one of three different species of kukri snakes in Asia.
According to the authors of the study, the three closely related species of snakes, all within the genus Oligodon, keep alive for up to several hours.
The footage below shows one – the Taiwanese kukri snake (Oligodon formosanus) – with his head buried deep in the belly of the banded bullfrog (Kaloula pulchra).
In the bloody attacks observed in the wild, frogs struggled to escape and ‘avoided being evicted alive’ – but their efforts were in vain.
The assaults can last up to several hours, depending on which organs the snake pulls out first.
An ocellated kukri snake (Vietnam) pierced this poisonous Asian frog for the first time and buried its head deep in the abdomen of the amphibian, because it probably ate the organs. However, as seen in the photo, the kukri snake swallowed the road completely
The footage also shows the ruthless snake repeatedly turning its body lengthwise in an elaborate execution known as a ‘death roll’.
“We believe that the purpose of these death scrolls was to tear out organs and then swallow them,” said study author Henrik Bringsøe, a herpetologist in Køge, Denmark.
Two of the three articles describing the gruesome behavior, all written by Bringsøe, were published this month.
One reports the gruesome feeding strategy of Taiwanese kukri snake (Oligodon formosanus) and the other the same strategy of Ocellated kukri snake (Oligodon ocellatus).
The other article, published in September last year, describes the same behavior in the small-bodied kukri snake (Oligodon fasciolatus).
The closely related three species of snakes in the genus Oligodon developed this unusual and disturbing behavior.
Still from the footage of a Taiwanese kukri snake that cut open the abdomen of a broken bullfrog (Kaloula pulchra) and extracted several organs that it bites and chews. The video shows how the snake is swallowing. The observation took place in Hong Kong. The full footage of this meeting can be seen below
It is interesting that it has also been recorded that these species are fed in a more conventional way – by swallowing their prey completely.
It is therefore likely that this alternative strategy has evolved to be able to eat much larger animals.
In one of the new studies, two cases are reported from Hong Kong where Taiwanese kukri snakes were observed untying the bullfrogs with straps.
In one case, the snake cut open the frog’s belly and placed its head in the frog’s belly before repeatedly performing its death role.
In the other case, the frog’s organs were forced out of the abdomen.
The second recently published research article describes the behavior of Ocellated kukri snake, which was observed eating the poisonous Asian black-spotted frog (Duttaphrynus melanostictus) in Vietnam.
It is known that Asian black spot frog secretes a powerful toxin from the parotid glands on the neck, but it apparently had no lethal effect on the predator.
Initially, the snake was seen burying its large head eyes deep in the abdomen of the amphibian.
Eventually, however, the snake swallowed the path completely, despite its toxicity, and provided evidence that kukri snakes are resistant to the cardiac glycoside toxins of the frogs.
The less recent newspaper of September was announcing the eating habit – described as ‘never seen in a snake before’.
It described several cases of the small-banded kukri snake (Oligodon fasciolatus) feeding on the Asian black-spotted frog.
At the time, the research team pointed out that smaller frogs of this species tend to be swallowed whole – possibly because they are less toxic than adults.
A small-banded kukri snake with its head through the right side of the abdomen of an Asian black-spotted frog, to extract and eat the organs. Tissue from a folded lung (top, left), and possibly adipose tissue, covered by clear liquid foam, as it mixes with air bubbles from the lung at expiration. The upper part of the forepaw is also covered by foaming blood, also mixed with air bubbles from the folded lung
In one of the new newspapers, Bringsøe and his team contain new details of a new sighting of the small-banded Kukri snake (Oligodon fasciolatus).
The team reveals that they prefer to swallow its prey altogether after doing the same ‘death role’.
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 eat.
“We hope that future observations can discover additional aspects of the fascinating feeding habits of kukri snakes, although we can indeed call it gruesome,” Bringsøe said.
All the research articles are published in the peer-reviewed, open access journal Herpetozoa.