Something that crocodiles do has made them one of the longest lasting species on Earth, specifically by allowing populations to explode after massive disasters.

The way it works is: about 90% of baby crocodiles are eaten by… adult crocodiles. So, when a natural disaster (say) wipes out huge quantities of adults at once, baby crocks find themselves in world mostly without predators that eat them, this living long enough to become adults. These adults go back to eating new babies, preventing the population from running amok.

If you imagine the “evil humanoid species™”—kobolds or whatever—does this, you can imagine why the “good guys” are always surprised at how the “hordes” replenish so quickly after being “culled”. You can also imagine the “culling” of adults erodes and annihilates any culture that might have existed in an endless downward spiral.

But, oh, “that’s OK because they’re cannibals”.