Aarhus University Seal / Aarhus Universitets segl


Harbour porpoises and prey capturing

The harbour porpoise hunts 24 hours a day
Photo AU
Porpoise released after being tagged
Porpoise tagged and released. Photo by Esteban Iglesias Rivas
Diving profile from a porpoise. Red colour indicates echolocation.
This is a porpoise diving profil, the black and white colour is illustrating day and night, red is marking the depth of were the echolocation clicks were made. Animation made by Wisniewska et al. 2016

This is the story about a world class hunter

The harbour porpoise is the smallest cetacean in Danish waters. It cost a lot of energy for a tiny whale to live in cold water, and especially in the winter time when it has to build up an isolating layer of blubber. This is why, it is so important for the porpoise to get enough to eat, and data recorded from acoustic dataloggers and tags, tells us, that the harbour porpoise hunts almost 24 hours a day. Scientists found that the porpoise is a world class hunter with a succes rate of 90% of all hunted fish. With a high energy loss in the cold water together with the amount lost during foraging and social interactions, this succes rate is highly important for the porpoise health, fitness and survival.

Read the scientific paper at:

This animation shows data recorded fra a tagged harbour porpoise. It begins with the porpoise breathing at the surface, then dives and start echolocating. During the dive you hear series of loud clicks with a high repetition rate, this indicates prey interaction. The animation ends with another trip to the surface and breathing. Wisniewska et al. 2016

Potential sleeping behavior

Harbour porpoises (Phocoena phocoena)

Harbour porpoise with tag
Harbour porpoise with tag photo AU

Harbour porpoises have like many other cetaceans, developed a way of sleeping without drowning. They actually only sleep with one half of the brain, while the other side keeps them breathing. The scientist here at the section of marine mammal research have tagged seven wild porpoises in 2010-2011 and found a very specialised diving pattern that could be connected to sleep. 

Access the full scientific article at ScienceDirect: