Although its name might imply that it is a “right whale”, the pygmy right whale is actually in a separate family and is not commonly regarded as one of the right whales. The falcate dorsal fin is set about two-thirds of the way back from the snout tip. This species is rather slender, resembling more the streamlined rorquals than the chunky right and bowhead whales; and the head is not large (less than one-quarter of the body length). The pygmy right whale is like the right whales in that it has an arched jawline; also the upper jaw curves downward toward the tip, although not as much as in right and bowhead whales. The flippers are small and slender with rounded tips. There are two shallow throat creases, reminiscent of those in gray whales.
The color of the body is dark gray above, ranging to white below. The flippers and flukes are dark gray. The baleen plates in this species number about 213-230 in each side of the upper jaw. They are up to 68 cm long and are said to be very flexible and tough. The color of the plates is yellowish-white. The fringes are the finest and densest among whales.
The maximum length recorded for a male is 6.1 m and that for a female is 6.5 m. They reach weights of at least 3,200 kg. At birth, pygmy right whales are about 2 m long.
Can be Confused With
This species can easily be confused with common and Antarctic minke whales, but the differences in head shape and the white flipper bands present in dwarf minke whales will allow differentiation when specimens are seen clearly. From a distance, the back and dorsal fin could be confused with those of a beaked whale; however, beaked whales have very different head shapes.
The pygmy right whale has a circumpolar distribution in both coastal and oceanic waters, and is known only from a small number of records in the Southern Hemisphere, between about 30°S and 55°S (north of the Antarctic Convergence). There appear to be concentrations in plankton-rich waters around continents and islands.
Ecology and Behavior
This is the least known of all the baleen whales. Groups of up to eight individuals have been seen, but singles or pairs are most common. Recently, a large aggregation of about 80 whales was observed in the southeast Indian Ocean, but groups this large are extremely uncommon. They are sometimes seen with other species of whales and dolphins.
The inconspicuous small blow and quick shallow surfacings of the pygmy right whale makes it difficult to spot and observe at sea. Sometimes, these animals bring their snout tips out of the water upon surfacing. Very little is known about reproduction in this species, but the breeding season is thought to be protracted. Sexual maturity is thought to occur at lengths greater than 5 m.
Feeding and Prey
Although there is little information on the diet, pygmy right whales are known to feed on calanoid and cyclopoid copepods, small euphausiids, and other small invertebrates (such as amphipods).
Threats and Status
This poorly-known species has never been commercially hunted. Although there is essentially nothing known of its status, there is no evidence that it is seriously threatened. It may be naturally rare, or perhaps its areas of concentration have not yet been discovered.
Currently, pygmy right whales are ‘Not Listed’ (IUCN) and ‘Not Listed’ (ESA).
Baker, A.N. 1985. Pygmy right whale Caperea marginata. pp. 345-354 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Volume 3: The sirenians and baleen whales. Academic Press
Kemper, C.M. 2002. Pygmy right whale. pp. 1010-1012 in W.F. Perrin, B. Wursig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
Ross, G.J.B., P.B. Best and B.G. Donnelly. 1975. New records of the pygmy right whale (Caperea marginata) from South Africa, with comments on distribution, migration, appearance, and behaviour. Journal of the Fisheries Research Board of Canada 32:1005-1017.