Book 11, Question 80
Why Do Venomous Snakes Have Venom?
Venomous snakes have venom because it helps them catch food and stay safe! Venom is a special kind of saliva with strong chemicals. Most snakes are not venomous and bite only when scared, so never touch a wild snake and tell a grown-up if you see one.
More fun facts
- Snakes use venom for two main jobs: overpowering prey before eating it and defending themselves from predators.
- Many snakes have venom that is especially deadly to the animals they eat most.
- Saw-scaled vipers that eat lots of arthropods have venoms that are more toxic to scorpions.
- Making venom costs a snake energy, and some snakes adjust how much venom they inject depending on the size of their prey.
- One sea snake that switched to a diet of fish eggs evolved to lose its venom.
- A survey of 368 people bitten 584 times by 192 kinds of snakes found that most bites caused fairly low pain in the first five minutes.
- Because defensive venoms usually hurt right away, that slow pain suggests most snake venom evolved mainly for catching food.
- There are exceptions: spitting cobras' venom causes intense pain if it gets in the eyes, which helps scare attackers away.
Sources: bangor.ac.uk, National Institutes of Health
Questions kids ask
Is snake venom mainly for defense?
Mostly no. Studies suggest venom evolved mainly to catch prey, though some snakes, like spitting cobras, also use it to defend themselves.
Why are snake venoms so different?
A snake's venom tends to match its food, like vipers that eat lots of arthropods having venom extra toxic to scorpions.