There has always been a little mystery behind birds that are known to be airborne for weeks, or months, as they set out for an overseas journey. Without a spot to land and rest, it has been assumed that certain species must be able to sleep and fly at the same time, but thanks to a group of researchers at the Max Planck Institute in Germany, we now have proof — they do!
Niels Rattenborg and his team of scientists rigged a set of frigatebirds with a small device that is able to record brain activity and head movement and found some impressive sleep patterns over a 1,850 mile non-stop journey.
Much like dolphins, the birds went into unihemispheric sleep where one half of their brain goes to sleep while the other half kept the bird navigating through the air. This form of sleep was what many researchers had assumed birds of this kind would do, but there was also a more interesting find in the study.
The scientists found that the birds would sometimes forgo the unihemispheric sleep pattern for a complete REM sleep, meaning they would often just coast while taking a snooze.
Unlike the typical human REM sleep cycle, the birds would only enter this sleep for a few brief seconds before regaining control.
These short bursts of sleep isn’t uncommon among species of birds, but that isn’t to say that they are well rested with the average 42 minutes of sleep per day. The frigatebirds species studied make up for the lost sleep though when they reach land, often logging 12 hours of sleep per day.