An overview of the most commonly observed social and feeding behaviours.
Head slapping thought to be a communicative signal. In this encounter, one individual continually slapped his head a total of 7 times whilst the others swam and breached near our boat. It may also represent aggressive behaviour, often towards a boat, particularly if there are calves present.
Logging is when the cetacean rests just beneath the surface with the top of its back and dorsal fin coming out of the water. This behaviour is often observed after a large feed and allows the animal to rest and conserve energy.
When a cetacean blows, it is exhaling air, before inhaling, to breathe. The blow-hole can empty and refill the lung in one fifth of a second. Blow is usually only seen in certain atmospheric conditions (when still and humid) and from a distance and normally is only seen in the larger baleen whales.
Foraging (Suspected Feeding)
Unless a fish is actually seen being chased, we can only guess that a porpoise, dolphin or whale is foraging based on its behaviour. When foraging, the individual or group, will be seen to surface in irregular directions and have no clear direction of movement. The group will often be seen to stay at roughly the same location for a few minutes. If the forage is successful, this behaviour will often be followed by fast swimming at the surface, whilst chasing the prey, followed by much slower swimming.
Spy hopping is a behaviour seen in many cetaceans and enables the animal to take a look above the surface, with the animal rising vertically out of the water. It could help in assessing the positioning of other members of the pod, look for bird activity to help find food or to take a look at human activity e.g boats.
Breaching refers to when an animal leaps fully clear of the water, often landing on their back, and is considered a social, playful behaviour. Often dolphins breach in synchronisation with one another, beautifully mimicking each other’s behaviour. Breaching may also help to build strength and muscle, reinforce relationships and strengthen communication skills. It is a behaviour commonly observed in all dolphin species, although many whales also breach. This photo is of a very young Risso’s dolphin calf learning to breach.
When travelling, the individual or group will spend much more time at the surface compared to when foraging, as it is more efficient to travel near the surface than to have to dive whilst travelling. The direction of the animal or group will also be fairly constant. Fast swimming can also be a type of travelling behaviour, but the animals will be creating white water as they move, unlike normal swimming and will often be moving at such speed, that a large proportion of their body will be seen during each surface (known as porpoising).
Before a young dolphin knows how to swim confidently they will often surface irrationally with their head high in the water.
Bow riding is a highly playful, social behaviour exhibited by many species of dolphin. Often a pod of dolphins will approach and swim at pace at the bow of a boat, breaching and swerving their bodies from side to side as they do so. Dolphins seem to really enjoy bow-riding but it may help to strengthen bonds within the pod.
Another method thought to be used to communicate with other members of the pod. Tail slapping may be used to alert others of danger or food, or may be a signal of irritation if disturbed by human activity for example.
Lunge feeding and bait balls
Lunge feeding is a behaviour observed in baleen whales when feeding on a bait ball (a very tight shoal of fish forced together into a ‘ball’). The whale will accelerate from below the bait ball with its mouth open wide, the fish are forced upwards towards the surface with nowhere to go and are consumed in great quantities by the whale. Bait balls are always a great attraction for other animals too, who work together to form the ball and feed off it. Dolphins and sharks are amongst the predators joining baleen whales for the feast. Marine birds swarm and dive in large numbers benefiting from the fish being driven up to the surface.
All baleen whales possess hair like ‘baleen plates’ made from keratin of which hundreds are present in each jaw. When feeding the whale will take in huge quantities of water and food and use the hairy plates to filter out the good bits, dispel the water and use their tongue to swallow the food.
Also known as Sonar, echolocation is the technique all Odontoceti (dolphins, porpoises and toothed whales) use to forage and navigate. A dolphin can produce a series of high frequency clicks which bounce back when they hit an object. The closer the object, the quicker the clicks take to come back, hence giving the dolphin a clear picture of exactly where the object is located. These amazing sound vibrations also give the dolphin information such as the size and shape of object and allows them to navigate their way around the ocean. To humans, echolocation can only be heard using specialist equipment, such as a hydrophone.