During the breeding season, polygynous male pectoral sandpipers that sleep the least sire the most young. Biologists have now discovered this extraordinary relationship. During three weeks of intense competition under the constant daylight of the Arctic summer, males actively court females and compete with other males. The most sleepless males were found to be the most successful in producing young.

Source: You snooze, you lose: Less sleep leads to more offspring in male pectoral sandpipers