Pilot whales use synchronized swimming when they sense danger

November 23, 2012

An international team of scientists have observed the behaviour of various groups of cetaceans in the Strait of Gibraltar and Cape Breton in Canada belonging to the Globicephala melas species, which are also known as long-finned pilot whales. These results show that these whales use synchronised swimming when they identify the presence of an external threat.

There are 300 pilot whales inhabiting the Straight of Gibraltar. Here these cetaceans remain throughout the entire year in the water of the Mediterranean and the Atlantic. But, little is known about their social structure.

Headed by the University of Aberdeen (United Kingdom) in collaboration with the Doñana Biological Station (CSIC) and Conservation, Information and Study on Cetaceans (CIRCE) group, the study analysed the patterns of association between individuals within this whale community. The aim was to provide a long-term vision of their social system.

"The important point is that we compared two different populations: one inhabiting the Strait of Gibraltar which is exposed to predators (boats in this case) and another with an ecotype where there are not so many boats (Cape Breton in Canada). The pilot whales are social species and we were interested in seeing how mothers teach their young, for example. We observed that they use synchronised swimming when in danger," as explained to SINC Renaud de Stephanis, researcher of the Biological Station of Doñana and coauthor of the study published in the journal Behavioural Processes.

Between 1999 and 2006 the scientists gathered samples in an area of 23,004 km in the Strait of Gibraltar and took 4,887 images of the dorsal fins of whales to compare them with those in Canada.

"They swim in complete synchrony both in the Strait of Gibraltar and Canada. When sea traffic or whale watching vessels are nearby, the whole group collectively reacts to such external stimuli. When we arrived at the watching area they were swimming at their normal rhythm but after 10 or 15 minutes near to them, the mothers and their young began to swim in a synchronised manner in alert position. This is a sign of affiliation to the group," adds the expert.

According to the researcher, these cetaceans also have a social structure formed by permanent partnerships. This means that they spend their life with the same whales and they do not interchange between different groups, as in the case of bottlenose dolphins.

Thanks to the study we now know that the presence of vessels also disturbs diving behaviour. "As such, when we began observing the whales up close, they tended to spend quite some time on the surface. However, the longer we spent nearby, the longer they stayed under water. This behavioural change could affect their energy levels, since they then have to make more of an effort to protect themselves and their young. In turn this limits hunting time, which means that they cannot feed their young properly," concludes the researcher.
-end-
References:

Valeria Senigaglia, Renaud de Stephanis, Phillippe Verborgh, David Lusseau. "The role of synchronized swimming as affiliative and anti-predatory behavior in long-finned pilot whales" Behavioural Processes 91 (2012) 8-14.

FECYT - Spanish Foundation for Science and Technology

Related Whales Articles from Brightsurf:

Blue whales change their tune before migrating
While parsing through years of recorded blue whale songs looking for seasonal patterns, researchers were surprised to observe that during feeding season in the summer, whales sing mainly at night, but as they prepare to migrate to their breeding grounds for the winter, this pattern reverses and the whales sing during the day.

Shhhh, the whales are resting
A Danish-Australian team of researchers recommend new guidelines for noise levels from whale-watching boats after having carried out experiments with humpback whales.

Fishing less could be a win for both lobstermen and endangered whales
A new study by researchers at Woods Hole Oceanographic Institution (WHOI) found that New England's historic lobster fishery may turn a higher profit by operating with less gear in the water and a shorter season.

North Atlantic right whales are in much poorer condition than Southern right whales
New research by an international team of scientists reveals that endangered North Atlantic right whales are in much poorer body condition than their counterparts in the southern hemisphere.

Solar storms could scramble whales' navigational sense
When our sun belches out a hot stream of charged particles in Earth's general direction, it doesn't just mess up communications satellites.

A better pregnancy test for whales
To determine whale pregnancy, researchers have relied on visual cues or hormone tests of blubber collected via darts, but the results were often inconclusive.

Why whales are so big, but not bigger
Whales' large bodies help them consume their prey at high efficiencies, a more than decade-long study of around 300 tagged whales now shows, but their gigantism is limited by prey availability and foraging efficiency.

Whales stop being socialites when boats are about
The noise and presence of boats can harm humpback whales' ability to communicate and socialise, in some cases reducing their communication range by a factor of four.

Endangered whales react to environmental changes
Some 'canaries' are 50 feet long, weigh 70 tons, and are nowhere near a coal mine.

Stranded whales detected from space
A new technique for analysing satellite images may help scientists detect and count stranded whales from space.

Read More: Whales News and Whales Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.