Risso’s dolphins have a distinctive grey body which over time becomes covered in scars. Atlas of Cetacean distribution in north-west European waters., Peterborough, U.K: Joint Nature Conservation Committee. The groups move to warm tropical waters in winter and head back toward the poles in summer. In mature males, the testicular mass represents 3% of the total body mass (Bloch et al. (2010). The species is usually cautious around vessels, making behavioural studies difficult. Within the Delphinid family, the species is closest related to false killer whale (Pseudoorca crassidens), melon headed whale (Peponocephala electra), pygmy killer whale (Feresa attenuata) and pilot whale (Globicephala sp) (Hartman et al. Nevertheless, this does not mean that they lack threats to its survival, as these include: – Intentional catch to obtain meat for the human consumption, bait for fishing and oil. Composition of a school of Risso’s dolphin, Grampus griseus. 2012). In other areas, Risso’s dolphins are considered a food resource and are taken intentionally or as by-catch. the bottlenose dolphin (Tursiops truncatus) (Hodgins, Dolman and Wier 2014). The species is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES). Fins are streamline and sloped backwards. 56-68. Species account by IUCN SSC Cetacean Specialist Group; regional assessment by European Mammal Assessment team. Best Time to Look. Kiszka, J., Macleod, K., Van Canneyt, O., Walker, D. and Ridoux, V. (2007). Researchers hypothesise that Risso’s dolphins use their teeth mostly in and for social interactions with conspecifics, which is thought to be the cause of the criss-cross scarring pattern on the animals. The mother cares the calf until it leaves the pod, a few time after being weaned at 12-18 months of age. Live in groups of up to. Scientific name: Grampus griseus. Movements Lutra, 47, 33-46. Modest, M. (2015). This species lives in pods of up to fifty individual animals, but pods of several hundred Risso’s dolphins have been sighted from time to time. Recreational disturbance, however, has also become of increasing concern in recent years. Risso’s dolphins are primarily found on the continental slope and outer shelf (400-1000 m) in areas where the topography of the bottom is steep (Hartman 2018, Jefferson et al. Icelandic: Höfrungur rissós Retrieved 5 July 2012 from www.iucnredlist.org. A large bulky dolphin with a bulbous head, no beak, a tall curved dorsal fin and elongated flippers. There are no estimates of global abundance for the species, but Risso’s dolphins are considered abundant in most of their distribution area. They can be very active and breach on multiple occasions or “porpoise” fast at the surface while travelling. Squid is thought to be the main source of food for the Risso’s dolphin, with the majority of feeding being done at night when squid move up into shallower water. Typically Risso’s dolphins are taken from the wild as calves and then brought up in captivity. Size: 3.2 m; Diet: Squid, octopus and cuttlefish; DESCRIPTION: A large bulky dolphin with a bulbous head, no beak, a tall curved dorsal fin and elongated flippers. Risso’s dolphins are protected in the North Atlantic. 2012). Their teeth only serve to hold their prey firmly, as this dolphin swallows its victims whole. Available from: St. Andrews University. The species have a whitish anchor-shape coloration patch on the chest between the flippers, which resembles that of pilot whales. Thanks to research, it is known that Risso’s dolphins spend almost 4 percent of their time resting, 5 percent feeding, 13 percent socializing and 77 percent traveling. Endangered Species Research, 31, 293-313. doi: 10.3354/esr00764, Smultea, M. A., Lomac-MacNair, K., Nations, C. S., McDonald, T. & Würsig, B. Norwegian: Arrdelfin, Danish: Risso’s delfin Several Risso’s dolphins together © Peter Evans. Another highly distinctive feature of Risso’s is the heavily scarred grey pigmentation of the adults. Aquatic Mammals 2018, 44(6), 653-667. doi:10.1578/AM.44.6.2018.653. Grampus griseus. 6: River dolphins and the larger toothed whales (pp. The Risso’s dolphin is a large, robust dolphin with an adult body length of 4 metres (13ft) and a square head with no beak. As the fifth largest member of the Delphinidae family, adult Risso’s dolphins reach up to four metres in length and weigh up to half a tonne. They tend to occur in deep waters (Hammond et al. Greenlandic: As the species is rare in this area, no common name has been given This species is generally found in deeper waters far away from land, but can occasionally be sighted near to the shore. In. Global climate change, range changes and potential implications for the conservation of marine cetaceans: a review and synthesis. the species and sub-species for which a strict protection regime must be applied across their entire natural range within the EU, both within and outside Natura 2000 sites. Risso’s dolphin jumping out of the water © Peter Evans. A Risso’s dolphin named Pelorus Jack became famous for guiding boats across Cook’s Strait in New Zealand between 1888 and 1912. Due to the blunt faced nature of these marine mammals they can sometimes be confused with pilot whales, therefore to identify this species it is advised to look for scarring on the body, caused by prey. 183-212). Impacts of climate change on marine mammals. The exact meaning of Grampus is not clear but is thought to originate from grandis piscis which translates to grand or big fish. Jefferson, Webber, Pitman. It avoids polar waters and likes those with temperatures between 15° to 20° Celsius but can thrive in waters up to 10° Celsius. Marine mammals: a review of status, distribution and interaction with fisheries in the Southwest Indian Ocean. Surveillance of individuals recognised by photo-identification of unique morphological traits (Photo-ID) suggests some stable bonds between non-related individuals within the pods, based on age and sex (Hartman et al. There are only regional/local abundance estimates for Risso’s dolphins and therefore no estimate of global abundance for this species. Griseus refers to the mottled grey colouration of the species. Some of the marks are also scratches from the beaks and suction cups of cephalopod prey. The countries that host the species include: Australia, Bahamas, Barbados, United Kingdom, United Arab Emirates, Peru, Philippines, Papua New Guinea, Madagascar, Mexico, Chile, China, Canada, United States, Cook Islands, Brazil, Cayman Islands, Argentina, Costa Rica, Haiti, India, Indonesia, Japan, Jamaica, Mozambique, Denmark, Ecuador, New Zealand, Taiwan and France. Also know as: Grampus Dolphin, Grey Dolphin. This convention aims to ensure conservation of wild flora and fauna species and their habitats. Tverlandet - Bodo, Norway. The species is protected by all NAMMCO member countries. Grampus griseus. 2010). Southampton, UK: The Mammal Society. It has a body mass of 300 to 500 kilograms. Special attention is given to endangered and vulnerable species, including endangered and vulnerable migratory species specified in appendices. The typical size of a Risso’s dolphin pod is between 3-30 animals, although “super-pods” of up to several thousand together have been observed, it is also very common for Risso’s dolphins to form travelling pods at sea with other dolphin species.