Penguins, like all seabirds, are known to be very vocal on the land where they breed. They use these vocalizations to help them get to know their friends and family.
Outside the breeding season, seabirds spend most of their life at sea and adapt to the marine environment where they feed. Penguins are very unique among seabirds for their extreme diving abilities. They can make a series of dives to a depth of 20 to 500 m (depending on the species) in search of fish, krill or squid.
Given the abilities of penguins, we wanted to know if they were making sound underwater. To do this, our research team (MAPRU) at Nelson Mandela University in South Africa has attached small DVRs with built-in microphones to the backs of three species of penguins.
Our research provides the first evidence that penguins make sounds underwater while hunting.
Burning penguins at sea.
Due to the difficulty of recording, very little was known about the vocalization of penguins when they are at sea. However, thanks to the latest technological developments, such observations are becoming available, in particular through the use of miniature video recorders.
We used DVRs and recorded 203 underwater vocalizations from all three species over nearly five hours of underwater shooting.
New questions arose from our observations. For example, how can penguins make such a sound underwater, given the high pressure at depth?
Are all these vocalizations signaling the same information? Do they produce other underwater vocalizations in different contexts? Are they related to the physiological needs of the predator for diving and feeding during apnea to correct buoyancy? Could they have a function in social interactions? Can they be part of a hunting technique and used to hit prey?
We hope that recent technological developments will continue to provide a deeper understanding of the fascinating behavior of penguins.
This article was published by The Conversation.
