November 24, 2012
Synchronized Swimming A Defense Mechanism For Pilot Whales
redOrbit Staff & Wire Reports - Your Universe Online
When long-finned pilot whales sense the presence of a potential danger, they use synchronized swimming as a defense mechanism, an international team of scientists has discovered.
Scientists from the University of Aberdeen in Scotland, the DoÃ±ana Biological Station (CSIC) and the Conservation, Information and Study on Cetaceans (CIRCE) studied the behavior of the approximately 300 members of the Globicephala melas species currently living in the Strait of Gibraltar and Cape Breton in Canada.
Their goal, according to a November 23 statement, was to learn more about the whales' social structure. They found the whale populations in each location were distinct.
The whales living in the Strait of Gibraltar were being exposed to boats housing predators while the ones in Cape Breton were less threatened by predators in boats, they explained in a study published recently in the journal Behavioural Processes.
Those conclusions came after the research team collected samples in an over 14,000 mile (23,000 kilometer) area in the Strait of Gibraltar, and also snapped more than 4,800 images of their dorsal fins, which were then compared with the Canadian whales.
"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," Renaud de Stephanis of the DoÃ±ana Biological Station, who was a co-author of the study, said.
"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 synchronized manner in alert position," he added. "This is a sign of affiliation to the group."
The researchers also discovered the pilot whales have a social structure that is based on permanent partnerships, meaning that they could spend their entire life with the same group of cetaceans without entering and exiting other groups like bottlenose dolphins do. The study also discovered the creatures' diving behaviors can be impacted by the presence of aquatic crafts.
"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," de Stephanis explained. "This behavioral 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."