Northern Right Whale

Northern right whales were named so due to their reputation for being the 'right' whale to hunt. They were once quite common in coastal waters, were slow moving, approachable, did not sink when killed, and provided large amounts of oil, meat and whalebone. 


Class: Mammalia
Order: Cetacea
Suborder: Mysticeti
Family: Balaenidae
Genus: Eubalaena
Species: glacialis
Common Names: Northern right whale
Irish Name: Míol mór an oighir; Ceartmhíol mór an tuaiscirt

Key identification features

Body length:  Up to 18m (females slightly longer than males)   
Weight: Up to 63,500kg
Blow: Wide, V-shaped, bushy blow reaching up to 5m 
Head: Large head up to one quarter the body length. Narrow arching rostrum with wart-like callosities, also found on lower lip and around the eyes. The largest callosity is called the “bonnet” located in front of the two widely divergent blowholes.
Dorsal/pectoral fins: No dorsal fin. Flippers are, blunt, broad and spatulate.
Colouration/markings: Robust, barrel shaped body is predominantly black with a variable amount of white on the belly. They have a broad back and large black flukes with a concave margin. There are no throat grooves in this species. Callosity patterns on the head may be used to identify individuals.

Field identification: at sea (behaviour)

Very little is known about their behaviour as they are quite rare in Irish waters. They tend to blow 5–-10 times at intervals of 15–-30 seconds followed by a dive.The surfacing sequence of the northern right whale begins with the appearance of the head clearing the water, upon which large amounts of callosities may be seen - callosities may appear white, pink, yellow or orange due to the presence of whale lice, also known as cyamid crustations. A V-shaped blow can then be seen which may reach up to 5m - on a windless day one can see that the left side of the V is taller than the right. Once the head has gone underwater, the smooth, broad, finless back will appear. The dark, triangular fluke is then often seen raised vertically out of the water before a deep dive which may last for as long as one hour, although more often dives last 5-20 minutes. 

Northern right whales are slow, docile swimmers but can often be seen breaching and flipper slapping. Breaches may occur up to 10 times in a row and can be heard from at least 1km away. 

Typically seen alone, they may also travel in groups of 1-3 animals but tend to congregate into larger groups during feeding events of 20+ individuals. When in small groups, normally only one animal will surface at a time. 

They are known to be quite inquisitive and approachable, and have been seen inspecting various objects in the water by pushing them around. 

Field identification: on land (strandings)

Baleen is grey with fine bristles, 200-270 plates per side and can reach up to 2.2m long.

Species similar in appearance

Humpback whales are slightly smaller and may occasionally produce a V-shaped blow. However, unlike the humpback whale, and northern right whale lacks a dorsal fin. 

Distribution and abundance

Northern right whales are confined to the North Pacific Ocean and the coastal waters of the east coast of North America - there have been less than 25 sightings in the last 60 years. They were once widely distributed on both sides of the Atlantic but numbers have since been dramatically reduced. Between 1908 and 1920 only 18 right whales were killed at the whaling station in Blacksod in Co. Mayo. This small number is an indication that their numbers were already severely depleted at that time. There have been a number of confirmed reports of individuals from European waters over the last decade, including two sightings from north-west of Donegal. The current North Atlantic population consists of approximately 300-350 individuals centered off the east coast of North America.

Despite complete protection of this species since 1935, it has not recovered and appears to be close to extinction in the eastern North Atlantic. They are primarily distributed in the western North Atlantic where they summer  between the Gulf of Maine and Newfoundland, with concentrations near Massachusetts and Nova Scotia. In the past they probably ranged from calving grounds in the Golfo de Cintra off western Sahara, through the Azores, western UK and Ireland, and the Norwegian sea to the North Cape. Recent calving areas have been located off Georgia and Florida in the United States. Wintering areas for most of the population are unknown.

Where and when best seen in Ireland

There have been a number of confirmed sightings in Irish waters over the last decade north-west of Donegal. 

Food and feeding

Right whales can be seen skimming through dense concentrations of zooplankton, primarily copepods, below or at the surface of the water - their most common prey item is the copepod. 

Reproduction and life cycle

Life expectancy: Up to 70 years 
Age of sexual maturity:  ♂14-15m, ♀6-12 years, 13-15m
Gestation period: 12 months
Calf weight / length at birth: 4.5-6m.
Calving frequency: 1 calf every 3-4 years
Calves born: Between autumn and winter
Calves weaned: 

In both real and relative terms, right whales have the largest testes and penises of any whales. Behavioural observations suggest that many males copulate with individual females and that there is very little male-male aggression, suggesting sperm competition as a reproductive strategy.

Social Structure and communication

Long term social bonding appears to be limited to mother-calf pairs. Although they tend to travel alone, they may be seen in groups of 2-3 individuals. Groups of 20+ individuals have been documented on feeding grounds. 

Status and conservation Issues

IUCN status: Endangered 

Conservation status in Ireland: Vagrant

The status of the northern right whale is highly endangered and their numbers are believed to be in decline. They are thought to be the closest to extinction of any other species of large whale, with an extremely low potential for recovery due to their slow breeding patterns and high mortality rates as a result of entanglement in fishing gear (particularly static gears such as gillnets and lobster pot lines) and collisions with ships.

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