In the deserts of the American Southwest, spadefoot toad tadpoles hatch in tiny oases. Until they develop into toadlets, they can’t survive outside of water, but these ponds are transient and quickly evaporate.
The tadpoles are in a race against the clock to grow up before their nurseries disappear. So nearly overnight, some of the brood explode in size.
They use their jack-o-lantern teeth and huge jaw muscles to devour their smaller pond mates. Nourished by this extra fuel, they develop quicker, leaving the pond before it can dry out.
The spadefoot toad is far from the only animal to eat members of its own species as a normal part of its life cycle. All of these animals do, too.
If that surprises you, you’re in good company. Until recently, scientists thought cannibalism was a rare response to starvation or other extreme stress. Well-known cannibals, like the praying mantis and black widow spider, were considered bizarre exceptions. But now, we know they more or less represent the rule.
For more cannibalistic creatures, check out the TED-Ed Lesson Cannibalism in the animal kingdom – Bill Schutt
Animation by Compote Collective