system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do birds and other small wildlife seem to have fast "twitchy" movements compared to humans and other bigger species.
gpt
It is generally their primary defense mechanism against their natural predators. A squirrel or hummingbird can't really fight a wild cat like a lynx, so they've evolved fast, unpredictable movement patterns, rapid tree climbing, digging dens deep into the ground or into trees, etc, etc.