Snakes borrow the poison of the toad to defend themselves

The toad species in Ishima Island (Japan) seems to be a loser in the evolutionary war with a snake. Not only were they unharmed after the toad, the snakes also stored the poison of the prey for self-defense and hunting.

Most snakes and other animals avoid toad eating due to fear of toxins in their skin. But the snake Rhabdophis tigrinus dared to do it. Deborah Hutchinson and colleagues at Old Dominion University in Norfolk, Virginia state, found that in the salivary glands of Rhabdophis tigrinus snakes on Ishima Island, there are bufadienolide compounds - toxins. which is only present on toad skin. Meanwhile, their congeners on Kinkazan Island - where there is no toad - do not have those compounds.

Snakes have no ability to synthesize their own toxins, so only bufadienolide compounds can be obtained from prey. To prove that judgment, Hutchinson's team selected a number of newly hatched Rhabdophis tigrinus and divided them into two groups. They fed a group of toad rations and the other group did not eat. After a while, the toads accumulate the poison of the toad at the salivary glands in the back of the neck, while the non-toad-eating group does not.

A snake Rhabdophis tigrinus. (Photo: Venomousreptiles)

"Rhabdophis tigrinus is the first species to use prey poison for self-defense and foraging purposes , " Hutchinson said.

In addition, when attacked, snakes on each island react differently. On Ishima Island, snakes straight up and spray poison into the enemy, while snakes on Kinkazan Island flee.

"The snakes on Kinkazan Island use less venom in self-defense than their counterparts on other islands, probably because they don't have much poison to threaten the enemy," Hutchinson said.

Scientists also found that high-toxin female snakes often transmit poison to the offspring. Therefore, snakes may not need to eat toads but still have poison to defend themselves.

Viet Linh