There are few things as impressive as a leaping dolphin, and there’s no doubt that a dolphin jumping high out of the water is the must have picture that everyone hopes to capture when they go out on a dolphin spotting trips.
But why do dolphins leap? The answer is we’re still not sure. Dolphins leap in a variety of situations – and probably for a variety of reasons too. The jumps themselves can be impressive. They can be partial breaches, where the animal slaps its body onto the water, clean leaps out of the water or acrobatic back flips and twists in mid-air. On rare occasions they have been observed jumping as high as 5 meters out of the water, which is higher than the dolphin itself is long!
One potential explanation for dolphins leaping or ‘breaching’ out of the water is that in certain situations, they may be doing it to save energy while they travel. If you have ever walked through water, you will know that it’s a lot harder than walking along the shore. Water offers much more resistance compared to air, and that’s why it is harder to move through it. The same may be true for dolphins. Although dolphins are perfectly streamlined, having no hind limbs and smooth skin to allow them to move swiftly through the water, by jumping out of the water, they may be able to increase their travelling speed. When groups of dolphins travel at speed, you will often see animals ‘porpoising’, a behaviour where the head and part of the body of the animal comes out of the water, rather than just their head.
However, conserving energy and travelling at speed is at odds with those impressive leaps when they jump nearly vertically out of the water. It may be that this is a way of communicating with other dolphins. While whistles and clicks, the normal sounds that dolphins make to communicate, travel a good distance underwater, the sound of half a ton of animal hitting the water with great force is sure to attract attention from much further afield! This type of communication could serve a number of different purposes. It tells other dolphins where that individual is, and, similarly, the dolphin can spot its surroundings better. It could alert other dolphins to the presence of prey, such as mackerel, or potentially the presence of a predator such as a shark or killer whale. Of course, our Cardigan Bay dolphins don’t have to worry too much about the presence of predators there – one of the reasons our bay is so popular with mums and calves is that it’s a safe place to raise their young with very few predators. Speaking of mums and calves, we often see dolphin mothers such as our resident females Ghost and Berry tail slapping when their calves are misbehaving or venturing too far away from them. In this situation we usually assume they are being called back or perhaps even being ‘told off’ for not obeying mum!
Another possible explanation is that the dolphins may be attempting to dislodge parasites. If you’ve ever jumped into a pool and landed the wrong way, you will know that hitting the water the wrong way can sting, but of course dolphins are unable to scratch themselves since they lack the hands to do so, so this may relieve any itchy areas.
We often see dolphins jump over and on top of each other when they are socialising, so leaping out of the water is likely to be a large part of play as well. Dolphins might try to escape a pursuer, jump over, or on top of, another dolphin, or maybe show off to a rival just how high they can jump.
Of course, there is also another explanation to all this. They could be doing it for fun!