Cetacean behaviour

Cetaceans display a huge range of different and interesting behaviours. As they spend the majority of their time underwater we get only a glimpse of their lives and behaviour at the surface.

When an animal comes to the surface in the normal course of their swimming
Sometimes people mistakenly refer to this as breaching because they are ‘breaching’ the surface of the water, but breaching is a different behaviour
Cetaceans come to the surface in an undulating up and down, or slightly rolling motion, rather than the side-to-side or snaking motion of sharks

All cetaceans have to breathe air at the surface, the loud, forceful exhalation of the larger whales can often be heard
In calm conditions the exhales of dolphins and porpoises can even be heard
The large whales may have a visible blow created by droplets of surface water causing a spray as they exhale
Some species have such a distinctive blow shape that it can be used to help identify them
- Fin whales have a straight blow up to 2m tall
- Humpback whales have a shorter, bushy blow
- Minke whale blow is only rarely visible when the conditions are perfect

A breach or leap is a jump with the full body leaving the water
This is typically seen most in the dolphin species, though most species will breach occasionally including large whales
Breaching is most likely a part of the social and communicative behaviours, it creates a visible and loud splash which can communicate presence and cohesion in a dispersed group

Head/tail slapping/tail-lobbing

A head slap is when an animal lifts its head out of the water and slaps it down on the surface
A tail slap if when an animal lifts its tail flukes and tail stock out of the water and slaps it down on the surface
A tail lob is usually seen in larger whales throwing their tail stock around above the surface and possibly slapping it on to the water surface
These behaviours could be similar to breaching in providing a social communicative function
They may also indicate some displeasure such as feeling disturbed by boat presence
They may act as a distraction when the group contains young, allowing mothers with calves to move away whilst attention is on the tail-slapping behaviour

Some species, particularly in the dolphins, like to ride the pressure wave at the bow of the boat
Depending on the speed of the boat they may do this for a few seconds or a few minutes
This behaviour may be combined with porpoising and breaching
Sometimes they will also swim and leap through the wake at the back of the boat
If a boat maintains a steady speed and course, the dolphins are comfortable knowing how close they can get to the boat
This is likely to just be an enjoyable behaviour, a form of play, and may strengthen social bonds in groups

Fast swimming in which the body of the animal leaves the water and skims along the surface is often referred to as porpoising
Our local species of harbour porpoise don’t tend to do this, but other species of porpoise do such as the Dall’s porpoise as well as dolphin species like the common dolphin

Logging

Logging is a form of resting when animals will float, like a log, at the surface for a number of minutes
Cetaceans are conscious breathers so they can only sleep with half of their brain at a time in order to remain half awake near the surface to continue breathing

Spy-hopping

Raising the head verticallly out of the water
The head is not slapped down like a head-slap, but gently raised and lowered
Cetacean eyesight works in air as well as underwater, so this behaviour allows them to look around above the surface

Cetacean behaviour

Surfacing/normal swimming

Blowing

Breaching/leaping

Head/tail slapping/tail-lobbing

Bow/wake riding

Porpoising/fast swimming

Logging