The frigatebird (Fregata minor), known for its incredible aerial stamina, showcases one of the most unique sleep behaviors in the animal kingdom. While most animals need to stop and rest to sleep, the frigatebird can sleep while flying—an essential adaptation for a bird that can remain airborne for up to two months without landing. Scientists studying these seabirds have discovered that they utilize unihemispheric slow-wave sleep, allowing one half of their brain to rest while the other remains alert to navigate and avoid obstacles.
In a 2016 study using EEG devices attached to the birds, researchers confirmed that frigatebirds sleep for only about 42 minutes per day when flying, often in brief 10-second bursts. This is in stark contrast to their sleep patterns on land, where they rest for up to 12 hours daily. Despite such minimal rest while airborne, their performance remains unaffected, raising fascinating questions about how they avoid cognitive impairment and maintain focus over long durations.
This unique adaptation underscores the extraordinary evolutionary paths some species have taken to survive extreme environments. For the frigatebird, sleeping in flight is not just a skill—it’s a necessity. By better understanding these birds’ neurological and behavioral patterns, scientists can gain insights into the flexibility of sleep and brain function across species, potentially unlocking applications in human sleep research and endurance studies.
