Did you know that bottlenose dolphins seen in the North Sea are some of the biggest in the world?
Last week Tom gave you an introduction to the harbour porpoises that we see here in the southern North Sea from the KING Seaways so I decided this week to talk about another North Sea species – the Bottlenose Dolphin.
Bottlenoses have achieved worldwide recognition; the quintessential dolphin that was the star of the popular TV show ‘Flipper’ as well as, sadly, of many hundreds of dolphin shows in aquariums worldwide thanks to their high intelligence and trainability. Their seemingly smiley faces and eagerness to interact with humans has furthered their magical reputation and put them at the top of many ‘favourite animal’ lists.
They are incredibly clever animals, coming in close to the top of all ranking lists of animal intelligence (alongside many other cetacean species) and have a wide range of communication methods from body language to the clicks and whistles that we associate with dolphin speech. Many, many different studies have been done on the subject of bottlenose communication both in captivity and in the wild and though complete understanding is still elusive, it does seem clear that the animals call each other by name using signature whistles that evoke a response from one particular animal within a pod. So those seemingly random high pitched noises we hear are the product of millennia of evolution, designed to help these dolphins bond together and form strong ties that will enable them to hunt, and survive, together.
However, the bottlenose’s have a darker reputation in the scientific world than the one they enjoy with the wider public. Mounting evidence paints a picture of a socially aggressive animal that on occasion seems to actively seek to hurt and injure others. Infanticide is a common behavior exhibited by male bottlenoses, which may be in order to free up the calf’s mother for mating again, but accounts of attacks on porpoises (a behavior frequently seen in the Moray Firth and other areas of the Scottish North Sea) and other species of dolphins, sometimes resulting in deaths, are harder to justify.
Yet, they do have redeeming qualities. In 2014 a group of researchers in French Polynesia found an unusual looking calf attached to a bottlenose mother. Further investigation revealed it was in fact a melon-headed whale calf that had somehow come under the young female’s protection despite her already having a calf of her own. She fed the calf her own milk and the pair stayed together for two years – around the usual length of time for a bottlenose calf to stay with its mother. How they came to be together is unknown but it is clear that the dolphin would have had no advantage in taking on a second offspring. Her actions may have been driven by maternal hormones but the outcome was pure altruism.
And finally, what of our bottlenoses here in the North Sea? They are some of the biggest bottlenose dolphins in the world. In harsh temperatures that sink to around 6 degrees Celsius in the winter these animals have to stay well insulated. They can grow up to 4m (and anecdotes of bigger sizes are increasingly common) and must put on enormous amounts of blubber in order to survive the cold. Many people are surprised at the staggering size of the bottlenoses found here, as the commonly photographed dolphin of tropical waters, the Indo-pacific bottlenose, is much smaller, usually only up to 2.8m.
Until this year, bottlenose dolphin sightings from the KING have been relatively infrequent and generally of individuals. In fact, before 2000, only 10 records had been made. This year from the KING alone we have made far more sightings that that. Their appearance on the North-East coast of England, and this year’s dominance over their white-beaked cousins cannot yet be explained. However, with hundreds of reports of bottlenoses from beach goers and dolphin lovers in dedicated social media groups, it is clear that they have captivated the local people. Whether or not the bottlenoses reappear in such large numbers next year remains to be seen but with some luck their presence will have encouraged people to make some changes to help protect the cetaceans species so close to our shores.
ORCA Wildlife Officer – The North Sea