The bottlenose dolphin

VIRTUAL ANIMAL IN AUGMENTED REALITY

The bottlenose dolphin is one of the impressive figures that you will be able to discover in the Grand Large experience.

Where is the animal to be found?

The bottlenose dolphin is a coastal animal, that can also be seen in rivers and estuaries. In tropical waters, groups bringing together around twenty individuals can live in the open sea. This species can be found in all of the world’s temperate and tropical seas: the Caribbean, North-West Atlantic, French Mediterranean, North-East Atlantic, English Channel, North Sea, and the Red Sea.

Bottlenose dolphins are often seen swimming in the wake of ships’ bow waves, which allows them to advance faster with less effort.

How can it be recognised?

• A large dolphin – it can measure anywhere between 2.5 and 3 metres – that is characterised by a spherical head forming a “melon” prolonged by a short snout that is called a rostrum. The lower jaw is longer than the upper jaw, and each one has between 20 and 26 pairs of teeth. Its dorsal fin has a concave shape curving backwards.
• The bottlenose dolphin is dark grey-brown in colour that can tend towards black with lighter shades on its flanks and a whitish belly.
• Its body is hydro-dynamically streamlined allowing it to swim at great speed. The dolphins’ skin is smooth because they lost their hairs as they evolved. This skin has the particularity of being elastic and it reacts to the undulations of the water to neutralise its disturbances. Furthermore it produces minuscule droplets of oil that lubricate the dolphin’s body, allowing the water to slide off.
• Scientists have shown a great interest in these features, and Max O. Kramer a German researcher has patented a material under the “Lamiflo” brand name that is based on the hydrodynamic properties of dolphin skin. An example of biomimicry, considered as a way of improving the propulsion of boats and aeroplanes.
• They feed mainly on fish, squid and crustaceans. This dolphin is a formidable hunter that operates alone or in groups using the fish-whacking technique where they throw fish up into the air, or stirring up the sediment to create a stream of mud to enclose their prey.

What is distinctive about it?

• The bottlenose dolphin, an excellent swimmer, can thus move through water at speeds of up to 40 km/h.
• It can also dive down to depths of 300 m and stay underwater for up to 15 minutes.
• Dolphins can hear frequencies 10 times higher than the limits of a human adult’s hearing.
• They have a sonar system that allows them to get an idea of their environment. This system – called echolocation – emits waves that come back as an echo, providing an acoustic image of the animal’s surroundings.
• Females reach sexual maturity at about 10 years of age and males at about 13. The mating season is in the summer, between June and September in the Northern Hemisphere, and between December and March in the Southern Hemisphere.
• After a 12-month gestation period the females give birth to a calf that they suckle for 12 to 18 months with a protein-rich milk. Female dolphins have a calf every 2 to 3 years.

Threat and protective measure

Human activities on the high seas – shipping in particular – can have a negative impact on dolphins. This is because the sound pollution caused by passing ships can upset these marine mammals’ behaviour and the functioning of their sonar.

In France it benefits from a special protective measure: Order of 27 July 1995 establishing the list of marine mammals protected on the national territory.