The truly marine aquatic mammals whales, dolphins and porpoises. This group has adapted to marine life with torpedo shaped streamlined bodies, forelimbs modified to flippers, almost no hair, no external organs and an insulating layer of blubber to help maintain a stable body temperature. Around the Devon coast there are several regularly seen groups of porpoises and bottle nosed dolphins. Larger whales and the more deep sea species are seen less frequently, but dead fin whales were washed ashore in south Devon and Cornwall over the winter of 2004 having died at sea. The Gulf Stream provides a migration route for many of these species, so occasional sightings are made.

(Phocoena phocoena)

Perhaps the most numerous marine mammal species in southwest waters and the most likely to be seen, there are also breeding populations of porpoise and plenty of live sightings.

Length: 1.4 – 1.9m. At birth 67 – 85cm.
Weight: 55 – 65kg. At birth 5kg
Food: Fish, sometimes squid, krill or other crustaceans
Found: Coastal waters of the sub-arctic and cool temperate waters of the North Atlantic, the North Pacific and Europe
Population: Some populations are declining but the global population is unknown.
Interesting facts: They are one of the shortest lived cetaceans, with only a few living past 12 years old.

There are breeding pods of bottlenose dolphin and common dolphin off the southwest coast and frequent sightings of live animals. Unfortunately there are a lot of dead strandings (particularly common dolphins and harbour porpoises) in the winter. There are occasional sightings and strandings of other species such as Risso’s dolphin, striped dolphin, Atlantic white-sided dolphin, white beaked dolphin, orca and long-finned pilot whale (although named as whales these last two are actually dolphins).

Bottlenose Dolphin (Tursiops truncatus)

Length: 1.9 – 4m. At birth 85 – 130cm
Weight: 150 – 650kg. At birth 15 – 30kg
Food: Fish, squid, krill and other crustaceans
Found: Most places around the world, but not polar regions. Inshore colonies do not migrate.
Population: Not known
Interesting facts: Very playful animals, often jumping right out of the water and performing entertaining acrobatic shows. They will swim and play in the bow waves of boats, getting pushed forwards by the pressure waves, but they have also been known to do the same with large whales!

Common Dolphin (Delphinus delphis)

Length: 1.7 – 2.4m. At birth 80cm
Weight: 70 – 110kg. Weight at birth not known.
Food: Fish and squid
Found: Very widespread populations, mainly living in deep waters, some colonies will migrate yearly and others will stay in the same place.
Population: Population not known, but it is estimated at a few million
Interesting facts: Their high-pitched voices they use for communicating with one another can sometimes be heard above water as well as below! They have a distinctive v-shaped marking on their flanks.

Risso’s Dolphin (Grampus griseus)

Length: 2.6 – 3.8m. At birth 1.3 – 1.7m
Weight: 300 – 500 kg
Food: Squid and fish
Found: Mainly deep offshore waters, but also found around the UK in the western parts of the English Channel, Irish sea, off Dyfed in Wales, west Scotland and the Isle of Mull.
Population: Relatively common in some parts but population unknown.
Interesting facts: When they get older they are heavily scarred by the teeth of other Risso’s Dolphins. They only have teeth on their lower jaw which are used for fighting and playing as well as eating. They move around in groups as large as 50 individuals, or as small as 3. These dolphins will jump and slap their fins on the surface of the water.

Long-finned Pilot Whale (Globicephala melas)

Length: 3.5 – 6.5m
Weight: up to 3 tonnes
Food: Squid and Fish
Found: They are found in cooler parts of the world, in both hemispheres, with a band separating them over the equator which they never cross.
Population: Unknown
Interesting facts: The Pilot Whale is not actually a whale, it belongs to a group of cetaceans called ‘blackfish’ which are in fact Dolphins.

Orca (Orcinus orca)

Length: 5 – 8m
Weight: Over 5 tonnes
Food: Other Whales, Sea-lions, Seals, Sea birds, Squid and Fish
Found: They are found all over the world, but prefer cooler waters where their only limit on their distribution is pack ice.
Population: Unknown, but declined in recent years due to hunting and other human interference.
Interesting facts: Orcas, like Pilot Whales are also a member of the group ‘blackfish’, meaning that they too are Dolphins. Possibly if they were more widely known as Dolphins people would less fear the Orca, or the ‘Killer’ Whale.

Rarely sighted but we are visited by several species of whale. Baleen whales are perhaps the most common, particularly the minke whale, but the fin and humpback whale have also been recorded. A surprising number of toothed whales have been recorded (many as dead strandings though). These include the pygmy sperm whale, Cuvier's beaked whale, Sowerby's beaked whale and northern bottlenose whale.

Sperm Whale (Physeter macrocephalus)

Length: 11 – 18m (males bigger than females). At birth 3.5 - 4.5m
Weight: 20 – 50 tonnes.
Food: Mostly squid and occasionally fish
Found: All over the world, except in the high Arctic. They prefer deep water and gather in large numbers where food is abundant.
Population: In 1940 is was estimated the population was 2 million however, due to hunting and other human interference, the population has steadily declined and, although we don’t know the current population, it is sure to be a lot smaller.
Interesting facts: They can dive up to 3000 meters at a rate of 3 meters a second and can stay down for up to 2 hours. Their head accounts for a third of their total body size and contains the world’s biggest brain, that still only accounts for 0.02% of his total body weight.

Cuvier’s Beaked Whale (Ziphius cavirostris)

Length: 5.5 – 7m. At birth 2 – 3m
Weight: 2 – 3 tonnes. At birth 250kg
Food: Fish, Squid
Found: All over, except for Polar Regions. Rarely found next to mainland, preferring deep open water.
Population: Unknown
Interesting facts: one of its other names is the Goose-beaked Whale, this is due to the striking resemblance its beak has to that of a goose when swimming.

Fin Whale (Balaenoptera physalus)

Length: 18 – 22m. At birth 6 – 6.5m
Weight: Anything from 30 to 80 tonnes
Food: Fish, krill and other crustaceans
Found: Deep water in the southern and northern hemispheres. Occasionally entering polar waters and rarely found in the tropics. They are mostly seen off Iceland, New England, Eastern Canada and the Mediterranean.
Population: Not known, but it is known that it is a lot smaller than it was in the past due to intensive hunting.
Interesting facts: The fin whale is one of the biggest animals on earth, second only to the blue whale. They can live an astonishing 100 years. Using low-frequency pulses they can communicate with each other over distances of around 500 miles! They also splash their tales in the water after breeching which they do regularly.

Minke Whale (Balaenoptera acutorostrata)

Length: 7 – 10m. At birth 2.4 – 2.8m
Weight: up to 10 tonnes
Food: Fish, krill and other crustaceans
Found: All over the world, favoring the cooler climates.
Population: Not known.
Interesting facts: The minke whale has a double blowhole. It breaks the water with its snout first when it breeches and rarely shows its flukes above water.