How Frigatebirds Stay Aloft For Weeks

Masters Of Endless Flight:

Frigatebirds are large seabirds known for their long wings and graceful flight. They spend most of their lives in the air, rarely landing on land or water. Unlike many birds, frigatebirds cannot swim well, so staying airborne is critical to their survival.

During long migrations, these birds may remain in the air for weeks at a time. Scientists once wondered how this was possible without rest. The answer lies in a rare and fascinating ability.

Sleeping With Half The Brain:

Frigatebirds can sleep while flying by resting only one half of their brain at a time. This type of sleep is called unihemispheric slow-wave sleep. One side of the brain sleeps while the other stays alert.

While half the brain rests, the bird keeps flying, adjusting its wings and staying aware of its surroundings. This allows the bird to rest without falling from the sky.

How Scientists Discovered This Ability:

Researchers studied frigatebirds by fitting them with small tracking devices that measured brain activity and movement. These devices recorded short periods of sleep during flight.

The data showed that frigatebirds sleep for only a few seconds at a time while airborne. Over many days, these short moments add up, giving the bird enough rest to function.

Why Frigatebirds Need This Skill:

Frigatebirds hunt flying fish and squid near the ocean surface. Food can be spread out over large areas, forcing the birds to travel great distances.

Landing on the ocean is dangerous for them because their feathers are not waterproof. Sleeping while flying helps them avoid landing and conserve energy during long trips.

Less Sleep Than Land Birds:

When frigatebirds are flying, they sleep far less than birds resting on land. They may get less than an hour of sleep per day while in the air.

Once they return to land, they sleep normally again. This shows that the reduced sleep is temporary and tied to their time spent flying.

A Rare Ability In The Animal World:

Only a few animals are known to sleep with half of their brain at a time. Dolphins and some seals use this method to breathe and stay alert in water.

Frigatebirds are one of the few flying animals known to do this. Their ability highlights how animals adapt to extreme environments.

What Frigatebirds Teach Us About Sleep:

The frigatebird’s sleep behavior shows that sleep can be flexible. While humans need long, uninterrupted rest, some animals survive on short, broken sleep when needed.

Studying frigatebirds helps scientists better understand sleep, adaptation, and survival in the natural world. These birds prove that rest does not always look the same for every species.