Risso´s Dolphin
| Scientific Name | Grampus griseus |  | |
| English Common Name | Risso´s Dolphin | ||
| Taxonomy | Class: Mammalia Order: Cetacea Sub-order: Odontoceti Family: Delphinidae Genus: Grampus Species: griseus | ||
| Behaviour | Risso’s dolphins do not bow-ride however some of the more curious individuals may approach a vessel. Not one of the most acrobatic of species, with a breach or a spy-hop being the most active they’ll get, except unless when they are travelling at any great speed when they are frequently known to porpoise. | ||
| World Distribution | Risso's dolphins have a wide distribution throughout tropical and warm temperate waters in both the northern and southern hemispheres. They prefer deep waters, although in some areas where either the continental shelf drop-off is close to shore, e.g. Azores, or where the sea-bed is over 100m deep, they can be found close to the shore. They prefer to keep within warmer waters, but sometimes have been spotted in cooler regions during the summer. | ||
| Morphology | Risso's dolphins are quite easy to identify, especially when they get older as they become extensively scarred due to being scratched by the teeth of other Risso's dolphins during their highly social interactions. They only have teeth in the front of their lower jaw and these are used when playing or fighting. Even between individuals there is extensive variation in colouration. Newborns are usually grey, becoming chocolate-brown and eventually pale grey with a pale underside. Some animals can be almost completely white, whilst others retain their dark grey colouration – all however will exhibit scarring to some degree. Flippers are long with pointed tips whilst flukes are broad with pointed tips. They have a very tall dorsal fin which can be up to 50cm in length, the tip of which may be curved or pointed. Instead of a beak, it has a blunt head with a bulging forehead that slopes steeply to the mouth which curves upwards. Newborns range from 1.3 to 1.7m in length and adults range from about 2.6 to 3.8m and weigh between 300 and 500kg. Risso’s dolphins live on squid and fish. | ||
| Threats | The primary threat is incidental entanglement in fishing nets. | ||
| Status | Abundance estimates are not available for this species. | ||
| Conservation Activities | The North and Baltic Sea populations are included in Appendix II of CMS. Protected under ACCOBAMS IUCN – Data Deficient | ||
