Dolphins can recognise their friends and family through taste, study finds

Bottlenose dolphins are able to recognise their friends and family without seeing or hearing them, researchers discovered.

While the animals have a sharp sense of hearing, they also have a unique ability to taste that allows them to identify other familiar dolphins using other senses.

Dolphins are regularly exposed to the taste of others of its kind, primarily through urine and other bodily excretions in the water.

Researchers at the University of St Andrews studied the animals in their natural habitat in waters surrounding Hawaii and Bermuda.

They tested how they reacted to urine samples from different individuals to see if they were able to distinguish between friends and strangers.

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The dolphins were found to have responded to samples from known animals for longer - despite having lost a lot of the common tastes found in other mammals.

Director of the Scottish Oceans Institute, Professor Vincent Janik, said: “Dolphins explored urine samples for longer if they came from known animals or when they were presented together with the dolphin’s unique and distinctive signature whistle, an acoustic identifier that works like a name.

“This shows not only that they can tell animals apart by taste, but also that they can recognise animals across their senses, hinting at a complex representation of familiar animals in a dolphin’s brain.”

He added: “While taste and smell are connected experiences for humans, dolphins have lost their sense of smell in their evolution and therefore could only use taste to solve the task set to them by the researchers.”

Despite having lost the ability to distinguish between the tastes - such as sour, sweet, umami and bitter - dolphins have unusual sensory cells on their tongues that help detect tastes of other animals.

Researchers trained the animals at the Scottish Oceans Institute to give urine samples when needed, creating a collection to present to the other mammals.

Professor Janik and his team will now try to understand what other information dolphins can extract from urine, possibly including information on diet or estrous cycle.