Biology

Study suggests snake venom evolved as a means of offense, not defense

Study suggests snake venom evo...
Although the krait's venom is lethal, the snake's bites are relatively painless
Although the krait's venom is lethal, the snake's bites are relatively painless
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Although the krait's venom is lethal, the snake's bites are relatively painless
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Although the krait's venom is lethal, the snake's bites are relatively painless

When it comes to human interactions with venomous snakes, we tend to think of that venom as something that was "designed" mainly for defense. A new study, however, suggests that it evolved first and foremost as a means of killing prey.

The research was conducted by scientists from Wales' Bangor University, working with colleagues from nearby Swansea University.

Under the supervision of Bangor's Dr. Wolfgang Wüster, zoology student Harry Ward-Smith started by gathering almost 400 online survey responses from reptile keepers, herpetologists, fieldworkers and other people who work with or around snakes. Of the approximately 600 snakebite incidents described, only a small amount were said to have involved immediate, severe pain.

This finding suggests that venom did not evolve primarily as a deterrent. After all, if an animal that was attacking a snake didn't experience any discomfort until considerably later, they likely wouldn't cease the attack, nor would they subsequently associate the pain with the snake. That's why bee stings are such an effective deterrent – they hurt right away.

"Even though we might have expected defending your life to be more important than feeding, it turns out that natural selection for diet does seem to be the main driver of venom evolution in snakes," says Wüster.

That said, a few exceptions to the delayed-reaction rule were noted as deserving further study. The venom that is spit by certain cobras, for instance, does act instantly.

A paper on the research was recently published in the journal Toxins.

Source: Swansea University via EurekAlert

2 comments
Brian M
Had presumed it had evolved primarily as a means of killing prey, the defence side being a fortuitous benefit, so nice that my unscientific assumption has some logic and evidence behind it!
Expanded Viewpoint
It has been known for many decades now, that venom from snakes and arachnids are a modified saliva, that can begin the digestive process. Venoms can be neuro-toxins as well as interrupting various chemical processes in the body or accelerating others. Instantly acting venom, causing pain and swelling, generally are deterrents, not made for attacks to garner prey.