Common Dolphins

©AK Wildlife Cruises

Natural history

Common dolphins have a unique “hourglass” marking on their side, which can be anything from pale cream to a yellowy-gold.
They have distinctive markings on their face, with a black eye patch and a stripe in the crease before the rostrum (beak).
They are a slender dolphin, up to about 2.7m in length for the larger males, and weigh up to 200kg.
They can reach speeds of 30 miles per hour.
They are born tail first, and stay with their mother for about two and a half years.
They live around 35 years.

An infant dolphin swimming close to its mother ©AK Wildlife Cruises

Family and social life

Around the world common dolphins can be seen in “superpods” of a thousand or more, and can join up with similar species such as striped dolphins (Stenella coeruleoalba). In Devon and Cornwall, they are seen in groups from three to a hundred or more!

Many whales and dolphins show strong family and social bonds. They also have “culture”, teaching each other where and how to forage, for example, or even how to migrate. Common dolphins are relatively understudied compared to bottlenose dolphins or killer whales, so one of our main aims at Dolphin Zone is to explore whether they too have their own culture.

Calf, juvenile and adult common dolphins swimming together suggest strong family bonds.

©AK Wildlife Cruises

Swimming

Dolphins in a hurry are usually “porpoising” - this is a fast movement with their body arching out of the water. You are likely to see splashes and flashes of fins and backs as they do this. Sometimes they are swimming more slowly, meandering along. We call this “milling”. At other times, they are so fast that they seem to be flying.

Common dolphins "porpoising" ©AK Wildlife Cruises

Breaching

Breaching is when the dolphin launches all of part of itself out of the water. This may be play, exercise, part of a feeding strategy, aggression or communication with each other. It may be all of those things at different times!

A spectacular common dolphin breach ©The Lone Kayaker

Feeding

Our dolphins seem to have many different feeding strategies. These vary according to prey and time of year, and different pods may even have different styles. One of the most spectacular is when we come across a multi-species feeding event, where gannets and other seabirds are seen circling above, and then diving amongst feeding dolphins.

Common dolphins feeding under gannets © Dolphin Zone

Communication

Dolphins have many ways to communicate with each other and find out about their environment. When they are nearby, we can often hear them whistling to each other...or perhaps to us? Sound travels further and faster underwater than it does in air, so they may be communicating across huge distances. They also use echolocation, which sounds like a series of clicks, to hunt, navigate and communicate. Behaviour can also be a communication - tail lobbing (where they bang their tails on the water surface) may be a warning to other dolphins, while rolling invites physical contact.

Interaction with humans

When dolphins choose to interact with boats, it is a magical experience. It is essential for their wellbeing that boaters are aware of how to behave around the dolphins, because being well-meaning isn't enough to ensure protection. The dolphins should always initiate the encounter and should never be pursued. Feeding should not be interrupted and extra care should be taken not to separate a group, especially if there are calves.

Helping dolphins in trouble

The WiSe scheme trains boat operators in best practice at sea, and is suitable for individuals and businesses.

Harassing whales, dolphins, porpoises and seals is a wildlife crime; if you see it happening please call 999.

If you see a whale, dolphin, porpoise or seal which is alive but unwell or injured, do not attempt rescue yourself. Putting them back in the sea can cause further distress. Please call British Divers Marine Life Rescue's emergency hotline on 01825 765546.

If you find a dead animal, on the coast, please call the Devon Marine Strandings hotline on 07719 086531 or email strandings@ devonwildlifetrust.org; for Cornwall call 0345 2012626. This helps us to gather essential information about the cause of death, which is used to protect marine species.