This is what researchers from the max planck institute for ornithology in the upper bavarian lake meadows report in the specialist journal "science". The animals are able to maintain high performance despite extremely reduced sleep during a three-week mating period, he says. They were active practically 95 percent of the time. This is remarkable, as the birds have just arrived in their breeding grounds in alaska from their long migration from their overwintering grounds in the southern hemisphere, write the researchers led by ornithologist and institute director bart kempenaers.
By forgoing sleep, the males increased their chances of encountering receptive females – and at the same time were better able to defend their territory. "Males must constantly fend off competitors by defending their territory and engaging in duels, while at the same time convincing females with extensive courtship behavior," said study leader kempenaers. Since the sun never completely sets in the arctic summer, the males that stayed awake around the clock were at an advantage. The male stranders who slept the least were therefore able to sire the most offspring. However, male stranders don’t care about their brood either.
The researchers monitored the animals with the help of GPS and transmitters that they stuck on their backs. The scientists determined the paternity of the offspring from DNA samples of all males, females and juveniles in the study area.
In extreme cases, the males slept an average of only 2.4 hours per day, while the slow sleepers among the animals managed 7.7 hours. Surprisingly, the short sleepers were nevertheless efficient. The trick: they fell from active wakefulness into deep sleep without any transition, thus saving the falling asleep phase. In addition, they slept very soundly and dreamlessly – apparently compensating for the lack of sleep. "Males who slept the least had the deepest sleep," says co-author niels rattenborg, who conducts sleep research at seewiesen.
The lack of sleep apparently had no health consequences – possibly even the opposite was the case. Successful males returned to the breeding area more often than males with fewer offspring and produced many young in the second year as well.
Researchers have not yet found a recipe for saving sleep in humans. Since not all the males coped equally well with the lack of sleep, the researchers assume that there are genetic factors involved. Even after the study, the scientists did not want to question the prevailing view that sleep serves to regenerate the brain.