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.
Mapping a System
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 analyzed the patterns of association between individuals within this whale community. The aim was to provide a long-term vision of their social system.
“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 synchronized 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.
Us and Them
Thanks to the study we now know that the presence of vessels also disturbs diving behavior. “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 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,” concludes the researcher.