Butterflies don’t sleep but enter a state of torpor. They lower their body temperature and heartbeat when they rest.
This fish stays awake and active for the first 22 weeks of its life. Only adults show signs of sleeping.
Bluefish migrate along the U.S. Atlantic coast and don’t sleep during that time. They also swim and react even when they seem to be sleeping.
Alpine swifts can fly for 200 days without landing. They nap in the air by gliding with their wings locked.
Orcas sleep with half of their brain at a time. They keep one eye open and one eye closed while swimming slowly.
Fruit fly sleep patterns vary widely. Some sleep for 10 hours, some for 4 minutes, and some not at all.
They have no brains, so they can’t sleep by definition. A 2017 study did find that these jellyfish enter into what is similar to a sleep-like state.
Bullfrogs never seem to sleep but only rest with alertness. They only go into a long hibernation-like state once a year.
Baby dolphins and their mothers stay awake and alert for a month after birth. They also keep surfacing for air every few seconds.
These coastal nesters fly non-stop for two months without landing or resting anywhere.