This snake rips a hole in living toads’ stomachs to feast on their organs

It’s the first time that scientists have observed this behavior in the reptiles

small-banded kukri snake tearing open toad stomach

In this image, a small-banded kukri snake (Oligodon fasciolatus) has used its needlelike teeth to tear open the abdomen of a toxic Asian black-spotted toad (Duttaphrynus melanostictus) and feast on its insides.

W. Suthanthangjai, H. Bringsøe et al/Herpetozoa 2020

Some snakes eat toads by politely swallowing the creatures whole. Others saw a hole in a toad’s abdomen with their teeth, shove their heads in and gorge on organs and tissues — while the amphibian is still alive.

“Toads don’t have the same feelings and can’t sense pain in the same way as we can,” says Henrik Bringsøe, an amateur herpetologist who lives in Køge, Denmark. “But still, it must be the most horrible way of dying.”

In a new study, published September 11 in Herpetozoa, Bringsøe and his Thailand-based colleagues document three such attacks on toads by small-banded kukri snakes (Oligodon fasciolatus). It’s the first time that researchers have observed this behavior in snakes, though animals like crows or raccoons eat some toads in a similar fashion.

Small-banded kukri snakes are known to use their teeth — which resemble curved kukri knives used by Nepalese Gurkha soldiers — to tear into eggs. And like most snakes, O. fasciolatus also feed by swallowing their meals whole. The snakes may use the newly described method, the researchers say, to best evade a toxin that the Asian black-spotted toad (Duttaphrynus melanostictus) secretes from glands on its neck and back (SN: 6/19/18).  

One Asian black-spotted toad was already dead when the children of coauthors Winai and Maneerat Suthanthangjai — both environmental researchers at Loei Rajabhat University in Loei, Thailand — stumbled upon a snake feasting on its innards near the city. But the whole area was bloody, and the snake had clearly dragged its prey around. It was clear “that it had been a true battlefield,” Bringsøe says.

Two other episodes at a nearby pond involved living Asian black-spotted toads. One fight that Winai watched lasted almost three hours, as a snake battled with the toad’s toxic defenses before finally winning. A kukri snake saws into its prey using its teeth like a steak knife, he says, “slowing cutting back and forth until it can put its head in” and eat the organs.

The reptiles may attack in this manner to help them dodge a toad’s poison, Bringsøe says, but it also may be a way for the snakes to eat prey that is too large to swallow. A fourth snake was spotted by coauthor Kanjana Nimnuam, a colleague of the Suthanthangjais, swallowing a smaller black-spotted toad whole.

Erin I. Garcia de Jesus is a staff writer at Science News. She holds a Ph.D. in microbiology from the University of Washington and a master’s in science communication from the University of California, Santa Cruz.

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