system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how do some animals float so well? Like ducks and beavers. Do they just have massive lungs?
gpt
Feathers and thick fur can keep pockets of air under them to give animals better buoyancy, a great example of this are otters. Birds actually have an easier time floating by default since their bones are a lot less dense than those of mammals are.