Colonies of breeding king penguins move like molecules in liquids, attracting and repelling each other in a familiar pattern, according to a new study by the (WHOI) and other agencies. This movement pattern helps the penguin community to stay close while protecting themselves against predators. In a video, as a seal approaches a penguin colony, only the penguins closest scurry away while the remainder stay in place, unperturbed.
King penguin couples lay a single egg each breeding season, then take turns cradling and incubating the egg on their feet. Breeding pairs gather to form large dense colonies (a king penguin colony on South Georgia Island at Salisbury Plain holds over 100,000 breeding pairs). The communities are full of early and later breeders, with an extended breeding cycle of over 14 months.
To study the colonies' structures, scientists monitored the movement of colonies on Crozet and Kerguelen islands over two years using aerial photographs taken from a helicopter. Using radial distribution function, a mathematical relationship that describes how atoms are arranged in solid, liquid or gas forms, they found the connection between breeding king penguins and liquid molecules.
"This liquid state is a compromise between density—or how compact the colony is—and flexibility, which allows the colony to adapt to both internal and external changes," explained senior author Daniel Zitterbart, a physicist at WHOI and adjunct scientist at the University of Erlangen-Nuernberg. The findings will help researchers better understand the species' vulnerability, especially as climate change threatens their habitats, forcing them to move further South.