Sex and sleep are two of the strongest drives in nature. If given a choice between the two of them, most animals would probably go with sex at first, but before long they'd succumb to sleep. There's one species of bird, though, that rarely chooses to sleep when there are mates to bed.
When given the opportunity, the pectoral sandpiper, a bird that spends its breeding season in the tundra of North America and Asia, prefers to go at it all night long, and into the next day, and into the following night, and into... well, you get the idea. Male sandpipers are so promiscuous that they have been recorded going nearly 3 weeks straight without sleep, all to satisfy their sex drives. That means they own the world record for the longest period of uninduced sleep deprivation in the animal kingdom, according to New Scientist.
If you had never heard this bird's mating call before, you might be forgiven for assuming it went like this: boom-chica-bow-wow. And if the male sandpipers have it their way, they're never with the same female twice.
Scientists recently observed these sleepless savants in action while studying a population of the birds near Barrow, Alaska. Radio tags were fitted on 149 birds, which accounted for most of the population in the area. Understandably, males were most active during periods of time when females were most fertile. Researchers were amazed, however, at their stamina. One male was recorded as being active 95 percent of the time for 19 days in a row.
Puzzled by how this was possible without sleep, researchers did something unprecedented: they fitted 29 of the males with devices that recorded their brain activity. Such has never been done before on wild birds. The data confirmed that the birds were running on little to no sleep, though it also showed that males who slept the least experienced the deepest sleep when they finally did rest, perhaps to compensate.
Then again, maybe they slept the deepest because they were also the most... satisfied? Incredibly, paternity tests found that the birds that were the most sleep deprived also fathered the most chicks. This means that, contrary to the prevailing wisdom, sleep deprivation did not hamper their performance. In fact, just the opposite seemed true.
"We thought sleep loss has an adverse effect on an animal's performance," said Niels Rattenborg, one of the members of the research team. "Yet certain male sandpipers sleep very little and perform the best."
Of course, it helps that there are nearly 24-hours of daylight during the summer in the Arctic. This provides little down time in the rhythm of the day, so males that stay awake can also mate most often with little regard to the passing of time.
The findings raise fascinating questions about why animals sleep at all. Though theories abound, scientists still haven't reached consensus on the purpose of sleep. The fact that these birds can go without sleep for so long, and without hampering performance, raises the issue about whether sleep is really essential. Then again, even these sandpipers did have to sleep eventually.
Some animals, such as dolphins, are capable of putting to sleep only one hemisphere of their brain at a time, which allows them to stay active even while sleeping. Other animals, such as many migrating birds, are known to take micro-naps while flying for long periods at a time. It's possible these sandpipers are employing a similar trick during their sex-capades, though more research needs to be done to know for sure.