Marine Living

"Cosmos," a humpback whale with an almost all-black tail, flukes in the Gulf of Maine. Cosmos was named for the galaxy-like pattern on its tail.

Jennifer Kennedy/Blue Ocean Society

Studying Individual Whales

Prior to the 1970s, knowledge about whales was gained primarily through the study of animals that were tagged or taken by whalers.

Since the 1970s, photo identification has become a primary method for studying whales. By photographing unique physical characteristics of the whale, such as dorsal fin shape and body coloration patterns, researchers are able to tell many individuals apart within a population of a particular species.

How to Tell Whales Apart

Each whale species has a set of distinctive features, which scientists use to identify individuals. One whale species that is fairly easy to distinguish is the humpback whale. Every humpback has a unique pattern on the underside of its tail, which is just like our fingerprint. The pattern ranges from all black to all white. A humpback whale will often lift its tail, or fluke, up when it dives, allowing a researcher to photograph this pattern.

Some whales do not life their tails up when they dive, or do not have a pattern on the underside of their tails. In this case, researchers have other methods to tell them apart. These may include distinguishing the whales by the shape of their dorsal fin, pigmentation patterns on their bodies, or by unique scars or markings on the whale.

Examples of other species that are studied using photo-identification are: Blue whales, which are identified using their mottled coloration pattern and dorsal fin shape Fin whales, which are identified using their dorsal fin shape, chevron pattern, and scarring Right whales, which are identified using the pattern of callosities on their headOrcas, which are identified using their dorsal fin and "saddle patch" behind the dorsal fin.

What Can Photo-Identification Tell Us?

Once a sighting record is established for an individual whale, researchers are able to study whale movements, migration, feeding patterns and life history (including age of maturity, calving interval and life span). Population estimates may also be obtained by tallying known individuals. Preferred feeding grounds can be noted as well, making it possible to identify locations as prime feeding areas and areas that may need protection.

Names for Whales

Researchers may see the same individuals year after year and many of the whales have been given names. The names usually relate to a marking on the whale so that the researchers will have an easier time remembering the name when they see the whale out on the water.

Using photo-identification, thousands of whales have been cataloged. In the Gulf of Maine, for example, many whales have "family trees" showing their lineages. One of the first whales identified in the Gulf of Maine was "Salt," a female whose dorsal fin is speckled white. Salt was first photographed in 1976 and has been seen nearly every year since. In 2008, she returned to the Gulf of Maine with her eleventh calf. Salt's family tree is extensive, and information such as this allows researchers to learn much about the life history of whales, such as calving intervals, if calves return to the same feeding and breeding grounds as their mothers, and how often they associate with their relatives.

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