Gentoo penguins live on the Antarctic peninsula, as well as many sub-antarctic islands. They hunt fish and krill in these freezing cold waters; and while hunting, they emit odd buzzing sounds. Scientists did not know the purpose of these vocalizations, until now.
Hunting as a Pack
Gentoo penguins are social animals. They live in complex social groups and use vocalizations to find mates, and to protect offspring and territory. But researchers have only just figured out how gentoo penguins use these vocalizations while hunting in the open ocean: They are hunting as a pack.
To study gentoo penguin calls in the water, researchers caught wild penguins and taped cameras to their backs before releasing them back into the water. They listened to the penguins make their calls and observed what happened.
In about half the cases the researchers observed, one penguin's call would elicit responses from other penguins who had been hunting in other areas of the water. Although they did not enter the water as a pack, the penguins formed a pack in response to vocalizations.
How does the pack hunt?
After the penguins called out to each other, the researchers observed, their dives became shallower and shorter. They also moved to new areas rather than lingering in the same place. The penguins appeared to keep track of each other's locations by vocalizing. Although the penguins did not move together as a group, the assumption is that they were on the hunt as a group.
Pack hunting is beneficial for gentoo penguins because they are more likely to find large patches of Antarctic krill when they work together. If one penguin finds a krill patch, it can alert the other pack members, and then everyone can come to the location to eat.
Gentoo penguins are not the only penguins to hunt in groups. Little penguins, also known as fairy penguins, actually synchronize their dives in order to catch prey. And many other penguin species use teamwork when they are hunting.