Solitary Dolphins: Risks and Responses

When solitude becomes unusual

Sometimes, however, an individual dolphin may remain on its own for an extended period, even limiting itself to a small area. These animals may be observed repeatedly near a particular buoy or a moored boat in a harbour. The dolphin’s proximity to humans is cause for concern as people may try to approach the dolphin and the dolphin may slowly start to show an interest in the people around them. Solitary dolphins interacting with people are called solitary-sociable dolphins by the scientists that have studied them. While the word “sociable” might sound friendly, the reality can be much more complex – and at times dangerous. Most recorded cases of solitary-sociable dolphins have been bottlenose dolphins, but other dolphin species have also exhibited this kind of behaviour. The majority of cases have been recorded in Europe but there are many other locations involved too. See the table below.

Risks for people

During a gradual process which has been described in the scientific literature, the dolphin’s behaviour and interactions with people can change significantly. The dolphin may actively seek out people especially those in the water and, depending on the individual dolphin, they may eventually behave in a way which could be rough and dangerous for humans in the water. Though the encounter may initially feel magical, the situation can quickly become risky:

• Dolphins are powerful animals capable of injuring people by biting, butting or breaching on top of them
• They may block a swimmer’s path, making it difficult for the person to leave the water
• Even seemingly playful behaviour can be rough and dangerous given the dolphin’s size and strength

Though serious injuries are rare, they do occur, and it is essential to warn the public of the dangers.

Risks for the dolphin

Keeping a solitary-sociable dolphin out of harm’s way is an almost impossible task. The animal is highly mobile and may change location over their lifetime, and it is also inherently difficult to police what happens out at sea. The animal’s determination, once fully habituated to interact with us, often puts them in harm’s way and water-users rarely understand the risk that the animal faces including:

• Boat strikes: many solitary-sociable dolphins have been injured or killed by vessels
• Deliberate harm: some have been attacked by people who felt annoyed or threatened
• Entanglement: there are incidents of solitary cetaceans becoming entangled in fishing gear or mooring lines
• Lack of time for natural behaviour: time for resting or foraging may be reduced due to interactions with humans

Every dolphin is unique

It should be noted that progression through the stages of sociability described here is not inevitable and there are cases of individuals returning to live with other dolphins after a time of being solitary. Some solitary-sociable dolphins also have occasional interactions with other dolphins despite spending most of their time on their own. All these animals have their own personalities and outcomes can vary.

How we can help

The best thing that we can do when a solitary dolphin takes up residence in an area is to not interact with them and thereby not encourage them to become habituated to humans. The most effective way to project both dolphins and people is to follow these instructions to ensure Dolphin CARE:

Choose not to disturb or otherwise interact with the dolphin
Alert the local authorities or marine organisations if necessary
Respect the dolphin
Enjoy watching from a distance.

If you are navigating in a vessel near a solitary dolphin, it is important to slow down and maintain a steady course in order to reduce the risk of a propeller injury.

OceanCare and solitary dolphins

OceanCare’s Director of Science, Mark P. Simmonds and Senior Science Officer, Laetitia Nunny have been interested in solitary dolphins for several years and have published numerous articles on the topic (see below).

As members of the Marine Animal Rescue Coalition’s Solitary Dolphins Working Group they offer support to relevant stakeholders regarding how to interact with solitary dolphins and how to manage them.

Articles by Mark P. Simmonds and Laetitia Nunny

• A Global Reassessment of Solitary-Sociable Dolphins by Laetitia Nunny and Mark P. Simmonds. Article published in 2019 in Frontiers in Veterinary Science.
• Marine Mammals Seeking Human Company by Mark P. Simmonds and Laetitia Nunny. Book chapter published in 2022 in the book “Marine Mammals Seeking Human Company” edited by Giuseppe Notarbartolo di Sciara and Bernd Würsig. Publisher: Springer, Cham.
• Behavior of a Solitary Sociable Female Bottlenose Dolphin (Tursiops truncatus) off the Coast of Kent, Southeast England by Sonja Eisfeld, Mark P. Simmonds and Laura R. Stansfield.

More information

Remembering Confi: Goodbye to a Solitary Dolphin from Galicia

El precio de nuestro afecto: qué sucede cuando los delfines solitarios se hacen amigos nuestros