Rarely do scuba divers get to witness penguins hunting under water but if you should be lucky enough to do so, have a listen. The first evidence has just emerged that the seabirds vocalise while they’re diving for food.
Penguins are like all seabirds in being highly vocal on land, which helps them to recognise and communicate with mates and kin during breeding season. However, they spend the rest of their lives at sea where, unlike most seabirds, they are equipped to carry out often extreme dives while hunting for fish, krill or squid.
A team of researchers led by Andrea Thiebault from the Marine Apex Predator Research Unit (MAPRU) at South Africa’s Nelson Mandela University took advantage of recent technological developments to carry out research that would previously have proved challenging.
They caught specimens of three species of penguin – king, gentoo and macaroni – as they headed out to sea from their breeding colonies at Marion, a sub-Antarctic island off South Africa. They then attached miniaturised video-loggers with built-in microphones to their backs and let them go.
The species were selected for their diversity of feeding strategy. King penguins venture as deep as 200m in search of fish, while macaronis feed mostly on schooling krill no deeper than 10m, and gentoos pursue a variety of prey at a range of depths.
When the cameras were retrieved after a single foraging trip, the results surprised the researchers.
They had captured 203 underwater vocalisations from all three species over almost five hours of underwater footage. Most of these (168) came from the gentoos, with 34 from two king penguins and just one from a macaroni penguin.