Human Beings usually need 6-8 hours of sleep per day to maintain healthy cognitive functioning. Constant sleep deprivation may result in depression, hallucinations, memory loss, seizures and even death in extreme cases. In 1964, our abilities to keep awake were tested to its limit. As part of a Stanford University scientific experiment, a San Diego local named Randy Gardner remained awake for an astounding 11 days and 24 minutes, which amounted to 264.4 hours of being awake at a stretch.1 Human beings need sleep to function normally, the same cannot be said for the frigatebird. As part of a scientific study to monitor the sleep cycle of frigatebirds, researchers rounded up 15 frigatebirds and fitted them with special data logger helmets containing accelerometers and electroencephalograms. The helmet would measure the bird’s brain waves, in an attempt to decode its sleep cycle. Once the equipment was mounted on the test birds, they were released in the wild.
Results of the tests
German researchers, lead by Niels Rattenborg of Max Planck Institute, noted the following observations post the experiment:2
- The frigatebirds would sleep on the wing by shutting down half of their brain and keeping the other half active. A phenomenon known as unihemispheric sleep.
- The active half of their brain would aid the birds navigation abilities while in flight
- Frigatebirds would have one eye open at times during their sleep cycle to scout for danger or potential collisions
- The birds would also need to go to a deeper sleep cycle at times, where they entered REM sleep (deep sleep), this however lasted for roughly just 7-12 seconds at a stretch
- It was analyzed that the birds slept for an cumulative 42 minutes / day while airborne
- Once the bird reached its destination, it would compensate for lost sleep by indulging in longer than usual naps going over 12 hours / day.
This research was documented in a paper called ‘Evidence that birds sleep in mid-flight’