Photo-identification is a technique used to identify and track individuals of a wild animal study population over time. It relies on capturing photographs of distinctive characteristics such as skin or

pelage Fur is a thick growth of hair that covers the skin of mammals. It consists of a combination of oily #Guard hair, guard hair on top and thick #Down hair, underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as ...

patterns or scars from the animal. In

cetaceans Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel them ...

, the

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

area and tail flukes are commonly used. Photo-identification is generally used as an alternative to other, invasive methods of tagging that require attaching a device to each individual. The technique enables precise counting, rather than rough estimation, of the number of animals in a population. It also allows researchers to perform

longitudinal studies A longitudinal study (or longitudinal survey, or panel study) is a research design that involves repeated observations of the same variables (e.g., people) over short or long periods of time (i.e., uses longitudinal data). It is often a type of obs ...

of individuals over many years, yielding data about the lifecycle, lifespan, migration patterns, and social relationships of the animals. Species that are studied using photo-identification techniques include: *

Killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white pa ...

s *

Humpback whale The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hump ...

s *

Whale sharks The whale shark (''Rhincodon typus'') is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. The largest confirmed individual had a length of .McClain CR, Balk MA, Benfield MC, Branch TA, Chen C, Cosgrove J, ...

Manta rays Manta rays are large rays belonging to the genus ''Mobula'' (formerly its own genus ''Manta''). The larger species, '' M. birostris'', reaches in width, while the smaller, '' M. alfredi'', reaches . Both have triangular pectoral fins, horn-s ...

- see Manta Matcher *Octopuses ('' Wunderpus photogenicus'') *

Salamanders Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten ...

Giraffes The giraffe is a large African hoofed mammal belonging to the genus ''Giraffa''. It is the tallest living terrestrial animal and the largest ruminant on Earth. Traditionally, giraffes were thought to be one species, ''Giraffa camelopardalis ...

Killer whales

Here are links to killer whales photo-identification databases:
Killer whales of southern AlaskaRussian Orcas
*
Icelandic Orca Project
*
Norwegian Orca ID Catalogue

References

*{{cite book, last=Obee, first=Bruce, author2=Graeme Ellis , title=Guardians of the Whales: The Quest to Study Whales in the Wild, editor=Elaine Jones, publisher=Whitecap Books, location=North Vancouver, British Columbia, date=1992, isbn=0-88240-428-8 Zoology Animal identification Applications of computer vision

Killer whales

See also

References