Why do dolphins jump out of the water?
- Written by Katharina J. Peters, Lecturer in Biological Sciences, University of Wollongong
Why do dolphins jump out of the water?
Charlize, age 8, Melbourne
Have you ever seen images of dolphins jumping out of the waves and performing impressive acrobatics in the air? Or maybe you’ve seen it in real life?
When a dolphin jumps, it can launch its whole body out of the water. While it looks like fun, it must also be hard work!
So, why do dolphins jump out of the water? There are several possible reasons. Let’s jump in and explore them.
To stay in touch
Dolphins are social animals and live in groups. But it’s hard to see long distances underwater. So, they use the power of sound to stay in contact with each other.
Sound travels much farther underwater than through the air. When dolphins jump, the slap of the landing makes a loud noise, and would be heard some distance away.
Some species, such as spinner dolphins, use jumping to communicate their location to other group members, especially at night. This helps them keep track of each other.
As an aside, spinner dolphins are very skilled jumpers. As the name suggests, they spin up to seven times in the air before landing back in the water!
Spinner dolphins are the acrobats of the sea.The need for speed
Have you ever tried to walk underwater? You will have felt how hard it is. That’s because water is more dense than air, which creates a “drag”, or resistance.
Dolphins have streamlined bodies to reduce drag, but they still feel it. So, if they want to travel quickly – for example, if they are trying to escape a predator or hunt fish – they sometimes jump.
While in the air, they travel faster than they would through water, and also save energy.
To gather food
Some dolphins weigh less than 50 kilograms, such as the Hector’s dolphin. Others weigh several tonnes, such as an orca.
Either way, when a dolphin crashes back into the water, you can be sure it makes quite a noisy splash.
Some dolphin species, such as dusky dolphins, use this noise to herd fish at the surface to make them easier to capture.
Shaking off hitchhikers
Fish called remoras can attach themselves to dolphins using a sucker on their head. This is good for the fish, because it can keep them safe and they have plenty to eat, such as small parasites and old bits of dolphin skin.
While the remoras don’t hurt the dolphin, they probably slow it down. So dolphins may try to get rid of the little hitchhikers by jumping to dislodge them.
A dolphin calf jumping to remove remoras.Fighting and frolicking
Dolphins are highly intelligent animals. They have big brains and can learn tricks and solve puzzles. With intelligence also come other traits: playfulness and social behaviour.
Sometimes, that social behaviour can end in a “fight”. Dolphin experts say two dolphins jumping around together might be actually trying to hit each other!
Dolphins also love to frolic – not just with each other but with other marine mammals such as whales and sea lions, with turtles – or even just a piece of seaweed! So they might jump as some sort of “game”.
As you can see, dolphins may jump for a range of reasons – sometimes just because it’s really fun!
Authors: Katharina J. Peters, Lecturer in Biological Sciences, University of Wollongong
Read more https://theconversation.com/curious-kids-why-do-dolphins-jump-out-of-the-water-256462
