Stupid.

Some birds don’t fly, but a few fish and several mammals can. Some birds can float, but a floating fish is usually dead.
A penguin has wings and can’t fly, but it can swim and walk on land. Otters also walk on land and are great swimmers but don’t have wings. A duck-billed platypus doesn’t have wings, walks on land and swims but can’t fly, but has a beak.
Some squirrels have wings and some don’t. None of them can fly, but they all are annoying.
Turtles and alligators lay their eggs on land but live in water most of the time. Toads lay their eggs in water but only live on land.
And then there are humans, don’t even get me started.