Fundación Cethus carried out research on Orcas (Orcinus orca), and spent more than 2,000 hours watching them. Despite having identified 30 individuals out of about 75, a group of 10 frequently visit the waters of the Península Valdés.
These animals divide into family groups and are described in the Population of North Patagonia as the Northern Patagonia Groups (PN) A, B and C.
Photo-identification work on individuals is being carried out in this area, and this technique has allowed us to determine:
-  community social structure
-  annual distribution
-  predation technique
-  how closely related the individuals are
The preliminary study of their sounds indicates that these groups of orca have a common ancestor. In Argentine waters it is evident that orcas predate 15 types of prey, including marine mammals, fish and sea and coastal birds.
The project is sponsored by the Whale and Dolphin Conservation Society and is supported by the provincial Office of Tourism (Chubut Province) and the Argentine Naval Prefecture.

Getting to know the Orca
The Orca is the only species of the genus Orcinus and is possibly one of the best-known and most studied dolphins.

Physical characteristics
This species, the largest of all the dolphins, has a very sturdy body, whose colour pattern is predominantly black with the exception of a white patch behind the eye, and a greyish-white area called a saddle patch behind the dorsal fin.
The head is conical and lacks a well-defined beak. 10-14 pairs of teeth are present in both jaws. Its pectoral fins are large and rounded, and the dorsal fin is located halfway down the back in front of the saddle patch. There is clear sexual dimorphism with the male presenting very well developed flippers and fluke, and a dorsal fin which starts to grow on reaching sexual maturity, gradually taking on a triangular shape, whilst in the females and juveniles it is smaller and falcate.

Distribution
Orca is to be found in all the oceans of the world and is considered a cosmopolitan species, although it usually inhabits cold temperate waters at high latitudes.

Biology and Ecology
The world population of Orca appears to consist of specialised sub-populations, or differentiated morphologically, behaviourally, ecologically and genetically in order to be able to adapt to different environmental conditions. This has led many researchers to speculate on the existence of races, eco-types and sub-species, even of different species.
A feature of orca is that they possess a rather complex social structure, spending their lifetime within a family group led by the eldest female who is usually related to each individual in the group. They have also developed dialects which differ from group to group but which contain basic shared elements.
They mainly feed on fish, seabirds, turtles and warm-blooded mammals, depending on the population we are dealing with. They often hunt in groups, sometimes beaching on purpose to capture certain prey, techniques which the calves learn from the adults. They have no natural predators.

Conservation
One of the threats this species face is related, as with the majority of cetaceans, to the destruction of its habitat, over-fishing, and pollution, but, actually, one of the greatest threats come from being killed in conflicts with the fishing industry, and in being captured for exhibition. Orca are a species which clearly are not able to adapt to life in captivity, and those animals caught for aquariums live on average only five and a half years, in comparison to those in the wild which have a far greater life expectancy.
The IUCN considers the species in the Data Deficient (DD) category, in the sub-category Conservation Dependant (CD), and it is listed in Appendix II of CITES.