Friends taught the dolphins to get the fish from the shells

Indian bottlenose dolphins (Tursiops aduncus) learn how to pull the fish from the shells of shellfish, from an unrelated friendly species, reported in Current Biology. Such horizontal learning, where knowledge is not transmitted from parents or older individuals descendants, and between animals of the same age (and probably experience), the toothed whales the evidence described for the first time.

Animals who long to care for the offspring, parents teach children various skills, primarily to produce food: it is called vertical training. However, the types of species which form large groups and tolerant to different members capable of sloping the training — transfer of skills youngsters from more Mature individuals, but no parents. Perhaps horizontal learning — situation where the source of knowledge becomes an animal of the same age. Most often it occurs in great apes.

It is known that the bottlenose dolphins of the Indian parents show children how to hunt fish, but other types of training they have previously recorded. Now scientists from the UK, Germany and Switzerland, led by Sonia wild (Anna Wild) from the Institute of biology of behaviour, max Planck society has collected data that helped to clarify the existence of different forms of knowledge transfer in this species. Researchers in the years 2007-2018 watched the dolphins from boats in shark Bay in Western Australia.

For all time, scientists met with Indian groups of bottlenose dolphins 5278 times. Each individual possibly identified: only counted 1035 individuals, however, when data analysis took into account only those of bottlenose dolphins, which were seen five times or more, and is only 538 individuals. From 295 take samples of nuclear and mitochondrial DNA to determine gender and degree of kinship with other dolphins. Video filmed behaviour patterns of bottlenose dolphins, including moments when the mammal brings to the surface the shell of a large mollusk turbinella and shakes her (in the English language this is called shelling or conching). This method of hunting dolphins chasing fish, that swims in the sink, the owner of which has died and is trapped.

Only video got 42 cases of shaking a fish out of shells. Most likely, there were more, but scientists were able to see everything, as the process lasts only a few seconds. The researchers analyzed what individuals at what point they saw this hunting behavior, and calculated its probable source on the basis of relations between individuals — both related (mother and cub), and friendly (peers who stick together).

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