Right whales have rotund bodies with arching rostrums, V-shaped blowholes and dark gray or black skin.

In the Northern Hemisphere, right whales tend to avoid open waters and stay close to peninsulas and bays and on continental shelves, as these areas offer greater shelter and an abundance of their preferred foods.

In the Southern Hemisphere, right whales feed far offshore in summer, but a large portion of the population occur in near-shore waters in winter.

During courtship, males gather into large groups to compete for a single female, suggesting that sperm competition is an important factor in mating behavior.

[17] A 2007 study by Churchill provided further evidence to conclude that the three different living right whale species constitute a distinct phylogenetic lineage from the bowhead, and properly belong to a separate genus.

The description of this species was based on a collection of fossil bones unearthed at Norra Vånga, Sweden, in 1705 and believed to be those of giants.

They have large, broad and blunt pectoral flippers and the deeply notched, smoothly tipped tail flukes make up to 40% of their body length.

In 2016, a competitive effort resulted in the use of facial recognition software to derive a process to uniquely identify right whales with about 87% accuracy based on their callosities.

[32][33] Many southern right whales are seen with rolls of fats behind blowholes that northern species often lack, and these are regarded as a sign of better health condition due to sufficient nutrition supply, and could have contributed in vast differences in recovery status between right whales in the southern and northern hemisphere, other than direct impacts by humankind.

This strongly suggests sperm competition is important in mating, which correlates to the fact that right whales are highly promiscuous.

The warm equatorial waters form a barrier that prevents mixing between the northern and southern groups with minor exclusions.

In northern spring, summer and autumn, they feed in areas off the Canadian and northeast U.S. coasts in a range stretching from New York to Newfoundland.

These are possibly the remains of a virtually extinct eastern Atlantic stock, but examination of old whalers' records suggests they are more likely to be strays.

[43] The Pacific species was historically found in summer from the Sea of Okhotsk in the west to the Gulf of Alaska in the east, generally north of 50°N.

More recent data from 2007 indicate those survey areas have shown evidence of strong recovery, with a population approaching twice that of a decade earlier.

It migrates north in winter for breeding, and can be seen around the coasts of Argentina, Australia, Brazil, Chile, Mozambique, New Zealand, South Africa and Uruguay.

Prey must occur in sufficient numbers to trigger the whale's interest, be large enough that the baleen plates can filter it, and be slow enough that it cannot escape.

The "skimming" may take place on the surface, underwater, or even at the seabed, indicated by mud occasionally observed on right whales' bodies.

Aside from the strong tails and massive heads equipped with callosities,[31] the sheer size of this animal is its best defense, making young calves the most vulnerable to orca and shark attacks.

Researchers speculate this information may be useful in attempts to reduce the number of ship-whale collisions or to encourage the whales to surface for ease of harvesting.

[43][46] During the mating season, which can occur at any time in the North Atlantic, right whales gather into "surface-active groups" made up of as many as 20 males consorting a single female.

Basque whalers reached eastern Canada by 1530[18] and the shores of Todos os Santos Bay (in Bahia, Brazil) by 1602.

Over the next hundred years, Yankee whaling spread into the Southern and Pacific Oceans, where the Americans were joined by fleets from several European nations.

[62] In winter in Argentina, Península Valdés in Patagonia hosts the largest breeding population of the species, with more than 2,000 animals catalogued by the Whale Conservation Institute and Ocean Alliance.

[67] In particular, they advocated 12 knots (22 km/h) speed limits for ships within 40 km (25 mi) of US ports in times of high right whale presence.

[68] The southern right whale, listed as "endangered" by CITES and "lower risk - conservation dependent" by the IUCN, is protected in the jurisdictional waters of all countries with known breeding populations (Argentina, Australia, Brazil, Chile, New Zealand, South Africa and Uruguay).

[71] A second major cause of morbidity and mortality in the North Atlantic right whale is entanglement in plastic fishing gear.

Right whales ingest plankton with wide-open mouths, risking entanglement in any rope or net fixed in the water column.

[76] In 2012, the U.S. Navy proposed to create a new undersea naval training range immediately adjacent to northern right whale calving grounds in shallow waters off the Florida/Georgia border.

Legal challenges by leading environmental groups including the Natural Resources Defense Council were denied in federal court, allowing the Navy to proceed.