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Right whales, as they are collectively known, are separated into three different species: The Southern right whale, North Pacific right whale and the North Atlantic right whale. Though these three species are distinct from one another, it was only until 2008 where three species were recognized, as the Northern Pacific and Atlantic right whales were both considered the same species until DNA sequencing proved otherwise.

An illustration of a North Atlantic right whale. Photo: Baleines en direct.


The two northern hemisphere species appear incredibly similar, thus making it difficult to distinguish the two species, while the southern right whale also appears virtually identical to its northern counterparts. All right whale species have a large dark robust body that lacks a dorsal fin or ridge. Perhaps the most distinguishing feature of these species however is seen in their head physiology. With their heads constituting around a quarter of their total body length and featuring an incredibly arched jaw (aiding in skimming for small copepod prey with their baleen), they also sport patches of callosities – a feature unique to whales. These hardened patches of skin appear white as vast numbers of whale lice congregate on them, creating unique patterns for each whale (which also helps with photo-ID!). These whales also have broad tails with a deep notch, helping distinguish the animals from other fluking species in their ranges. With their robust body comes incredible weight as well. The Southern right whale come in at an average of 49 feet, 104,000 pounds, North Atlantic right whale at an average of 52 feet, 144,000 pounds and the North Pacific right whale at an average of 60 feet, 180,000 pounds. For reference, this is basically the same length of a humpback whale, but twice the weight!

The callosities on right whales house thousands of sea lice, giving them a white appearance. Photo: Ocean Conservation Research.


The two northern species’ ranges feature very depleted stocks and may not range as far as historical populations. The North Pacific right whale have populations summering in the Bering Sea and Gulf of Alaska, as well as the Sea of Okhotsk and surrounding area in the west. The North Atlantic right whales migrate from the Labrador Sea in the summer to their calving grounds in Georgia and Florida in the winter. There are also very few individuals left in the Eastern Atlantic thought to migrate from Northern Europe to the Sahara, but with such few animals left, it is difficult to determine the true current range. The Southern right whale on the other hand, though also a reduced population, have much healthier numbers that migrate from Antarctica in the summer to higher latitudes in the winter, such as Australia.

Diet & Behavior

Like other large baleen whale species, right whales eat very small things – zooplankton, mainly tiny crustaceans such as copepods, euphausiids and cyprids.  But how they do this is different than other baleen whale species.  Most people are familiar with the lunge feeding done by humpbacks for example.  They swim quickly to the surface and lunge open mouth through the prey patch.  But right whales do what is called ram or skim feeding.  They open their mouths and slowly swim through patches of zooplankton (which can be as large as a grain of rice), and this can be done at any depth or at the surface.  It can be an interesting sight seeing the top of a whale’s mouth skimming across the surface of the water!  This technique requires a lot of surface area, so their baleen can reach up to 7-8ft in length! In comparison lunge feeding species average about 3ft.   Right whales an eat up to 2,200-5,500 lbs of food per day!

All right whales species are very slow swimmers. Despite their size and slow swimming, they can be very active at the surface. Northern Atlantic right whales will often breach and for surface active groups where mating and socializing occur in all seasons and habitats. They communicate through low-frequency moans, groans and pulses to maintain contact between individuals, communicate thrats, signal aggression or other social reasons. Description of specific behaviors is more detailed for Southern right whales. They will also breach, along with lobtailing (lifting and then slapping the fluke down on the surface), flippering (slapping the water surface with their pectoral flippers) and sailing (lifting their flukes up and holding them there, allowing the wind to move them).  Sailing is particularly cool – imagine using your tail like a kite!  Much less is knowing about the North Pacific right whale behavior, as very few are observed in the wild.

All right whale species females seem to give birth for the first time around 9-10 years of age and have a 12-13 month gestation period.  They will nurse their young for about a year, and calve every 3-5 years. However, that interval may be increasing to 6-10 years due to anthropogenic stressors like entanglement and vessel strikes (this also is affecting the sex ratio, where more females are dying, leaving there more males than females in the population – particularly for the North Atlantic species). Calves may swim on mom’s back, or butt them with their heads. Mom may roll over on their back and hold the calf in their flippers. It is less clear when males become sexually mature, but one thing that is interesting: they have the largest testicles in the animal world – each on can weigh 1 ton!

The migration routes are mostly known for the North Atlantic and Southern right whale species, but much less is known for the North Pacific species. Generally, right whales will calve in low latitude warm waters in winter, and then migrate to colder waters to feed during summer and early fall. The only known calving ground for the North Atlantic right whale is in the southeast U.S., around northern Florida and the Carolinas.


All right whale species are listed as Endangered under the Endangered Species Act (ESA), and “depleted” under the Marine Mammal Protection Act (MMPA).

A rare North Pacific right whale surfaces. Photo: Robert Pitman, NOAA.

There are estimated to be less than 400 North Atlantic right whales left, and of these fewer than 30 individuals in the eastern stock of North Atlantic right whales! North Pacific right whales are even rarer: there are thought to be less than 100 individuals left alive, however because this species is so hard to find and track we don’t have a great handle on the exact population number. Southern right whales seem to be doing (relatively!) better than their northern hemisphere cousins, with around 3-4,000 remaining. Their populations seem to be recovering, albeit slowly, following whaling.


  • Entanglement – This is the main threat for all three species of right whale. It is estimated that more than 85% of all North Atlantic right whales have been entangled at least once in their lives, and chronic entanglements are one of the reasons behind females having fewer calves and taking longer to start giving birth. The energetic cost of dragging hundreds of pounds of fishing gear on your body as you swim through the ocean is huge, and has a negative impact on foraging capability, health, and ability to maneuver which puts the whales at greater risk of ship strikes.
  • Vessel Strike – Right whales live in the same areas as major shipping lanes, especially those used by large oceanic ships, and being a slow-swimming whale they may not be able to move out of the way as quickly as some other species, making vessel strikes a real concern. Entangled individuals will find it even harder to move away from ships and may be more prone to vessel strikes.
  • Climate Change – North Atlantic right whales have actually been shifting their distribution in the last 10 years following prey, making it harder to predict where they will be and thus harder to protect them, especially as they move into areas that do not confer the same protection as their typical range. North Pacific right whales face another challenge from climate change: sea ice. Sea ice coverage is closely linked with zooplankton distribution and timing, but as sea ice decreases the zooplankton is shifting and moving in ways the right whales are unfamiliar with. These changes could result in starvation and stress to the North Pacific right whales, and for this species climate change is really the biggest threat.
  • Ocean Noise – Living in busy shipping areas, all right whale species are likely impacted by oceanic noise reducing or impeding their communication. Studies have shown that have shown a link between constant ocean noise created by shipping traffic leads to an increase in stress hormones North Atlantic right whales, thus there are also long-term health threats that could result from exposure to noise.
  • Biotoxins – Biotoxins produced by algal blooms can be a problem for right whales, with whales exhibiting odd or unusual behavior following exposure to the domoic acid and saxitoxin produced during these blooms. Whales may become disoriented, act out of character, or be less able to move out of the way of things like ships or fishing lines.
  • Predation – The Southern right whale is prey for large sharks and killer whales (orcas), especially around Australian waters. Kelp gulls are also known to harass these whales by pecking at their backs while they are at the surface!

Fun Facts

  • They are called “right whales” because they were literally the “right” whales to hunt! Right whales are slow swimmers, and their bodies float when killed, making them an easy target for whalers to catch and retrieve.
  • The North Atlantic right whale’s Latin name, Eubalaena glacialis, literally means “good/true whale of ice”. The North Pacific right whale and the Southern right whales are named after their geogrpahic locations, E. japonica and E. australis respectively.
  • The North Pacific right whale is thought to live up to 70 years old, and researchers use earwax to determine their age – the growth rings within the wax can be used just like tree rings! They can also obtain lots of other information from ear wax such as hormone shifts, years of nutritional stress, etc.
  • Our friends at Smelts are currently making huge strides towards protecting right whales (and other marine mammals) from entanglement by creating lineless fishing gear. Ropeless technology is a huge innovation that would not only stop entanglements and potentially save the North Atlantic right whale, but would also provide a safer and more reliable return of equipment and catch for the fishermen! Check out more about Smelts and their amazing work here.

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