Little Penguin Hunters

Aptly named little penguins, (Eudyptula minor) are the smallest of all penguin species, reaching just over a foot (33 centimeters) in height. They live in Australia and New Zealand, and due to their size, are often predated by species on land (cats, dogs, foxes and ferrets, to name a few), and at sea (fur seals and other marine mammals). And when it comes to hunting, these diminutive seabirds do something unusual —they occasionally hunt with other little penguins. Why? Sharing the spoils of foraging could be detrimental to natural competition.

Grace Sutton from the Deakin University in Australia mounted cameras on 21 little penguins to understand this behavior and little penguins’ general foraging behavior. Through these camera observations, she and her colleagues followed the birds on 295 prey encounters over long distances (50.3 kilometers on average) and deep dives (8.2 meters on average). The animals chomped down on krill and herring, anchovy and sprat, and surprisingly, jellyfish. Sutton points out in her recent publication in PLoS ONE, that it was likely unknown that little penguins consume jellyfish because jellyfishes’ “rapid digestive deterioration means they may often be overlooked in diet studies.”

In some cases the prey fish were solitary and in some instances, the fish were schooling. It was that factor that seemed to determine whether the penguins hunted alone or with partners, Sutton found. Perhaps not surprisingly, the little penguins associated with each other more often when hunting schooling prey than when encountering solitary prey. However, this didn’t lead to greater foraging achievements, just the opposite: success preying on schooling fish was similar or greater when individual penguins hunted on their own rather than together.

So why group hunt? Sutton has two ideas. Maybe group hunting increases the probability detecting prey, she and her team suggests. In addition, “birds may also congregate in groups at sea in order to reduce the likelihood of predation,” they write.

Or maybe hunting little penguins just appreciate a little company…

(You can watch two of these little penguin hunting videos here and here.)

Image: Magnus Kjaergaard/Wikipedia