The North Atlantic right whale is one of the rarest whale species in the world. With 356 individuals remaining, our researchers are working tirelessly to study and protect this critically endangered species.
Right whales feed on zooplankton, microscopic animals that aggregate in dense patches in certain areas of the ocean at certain times of year. The right whale’s preferred prey species is the rice-grain sized Calanus finmarchicus. Right whales are commonly found in areas with ultra-high densities of Calanus. Right whales are considered “grazers,” meaning that they feed by swimming slowly through patches of zooplankton with their mouths open and strain the water out through their long baleen plates.
Right Whale Appearance
The North Atlantic Right Whale has a few physical attributes that help to easily identify the species.
Right whales have large patches of raised tissue on their heads, called callosities (Kah-laus’-eh-tees). Some people confuse the callosities with barnacles because they appear to be white. Actually, the callosity tissue is dark like the whales skin, but it is infested with light colored cyamids (Si-am-ids), or ‘whale lice. Millions of these cyamids live on the whale’s head and can obscure the underlying callosity. Because they are light in color, they provide contrast against the black skin serving to define the outline of the callosity.
The placement and pattern of the callosity is unique to each individual and is how the scientists distinguish one right whale from another. The callosity begins to emerge shortly after birth, but the pattern is not was established until 7-10 months later. Although the height of the callosity can change throughout a whale’s life (i.e. grow upwards and break off repeatedly), the placement of the callosity on the whale’s head typically remains stable. In rare cases, some callosity tissue on adult whales develop in new places or disappears.
Like all mysticetes (whales with baleen instead of teeth), right whales have two blowholes. Unlink other mysticetes however, right whale blowholes are angled in such a way that when the whale exhales, the blow forms a V-Shape.
A right whale’s tail (or flukes) is all black, has a deep notch in the middle and a smooth , trailing edge. They frequently lift their flukes out of the water when diving.
Where Do Right Whales Live?
The right whale concentration zones are broken down into Southeastern United Staes, Northeastern United States, and other areas. All of these areas have varying primary uses for different times in the year.
Critical Habitats in the Northeastern United States and Canada
Cape Cod Bay and the surrounding waters serve as a feeding and nursery area. Although right whales have been found here in all months, their peak occurrence is March and April. Recent surveys indicate that more whales may be here in the winter months than previously thought. All age classes and both sexes use this area. Mothers and calves inhabit the area mostly in April and May, with some also appearing in the summer and fall. Two-thirds of the population has been seen here at some point. In recent years, over 200 individuals have been seen there annually.
The Great South Channel is a feeding/nursery area east of Cape Cod. It is inhabited primarily in April, May and June with relatively little survey effort there, a large portion of the population has been sighted here. All age classes and both sexes use this area. During good survey years, nearly 200 animals are seen here and more than 80 percent of the cataloged whales have been seen here at least once.
The Bay of Fundy is located between the state of Maine and Nova Scotia, Canada. The Bay of Fundy is an important feeding/nursery area. Whales are found here from June through October, with peak occurrence in August and September. All age classes and both sexes use this area. Between 150 and 200 animals used to be seen here annually, but recently the numbers of whale using the Bay has gone down and the residency times of those who do use it have shortened. More than 80 percent of the cataloged whales have been seen here at one time in their lives.
The Roseway Basin is a feeding area that is generally used during the same months as the Bay of Fundy – August through October. Adult males in social groups (Surface Active Groups or SAGs) dominate this area. Mothers and calves are very rare here. Over 100 whales have been documented here in a given season, and more than 50 perfect of the cataloged whales have been see here at least one. The use of this habitat has also decreased in recent years.
Critical Habitat off the Southeastern United States
This is the only known calving ground for the population. Occurrence is December through March with peak calving in December and January, and it is believed that no feeding takes place during this time. The area is frequented primarily by mothers, newborn calves and some juveniles, and occasionally by some adult males and non-calving adult females. The number of whales using this habitat annually has fluctuated more than any other habitat ranging from less than a dozen to over 250 individuals. More than two-thirds of the cataloged whales have been seen here at some point, although only an average of 50 animals are seen here in any given year.
Although the five critical habitats represent the majority of the right whale sightings historically, in the current decade, many right whales are using several other habitats as well. Two of those are the Gulf of St Lawrence and the waters south of Nantucket, MA. Right whales have been seen in the Gulf of St. Lawrence between May and December with as many as 150 individuals there annually. A mortality event that resulted in 12 right whale deaths there in 2017 drew international attention. The area south of Nantucket is slated for wind farm development and right whales have been seen in this area in all months except August and October- with the majority of the sightings in March and April.
Even with the addition of these habitats, we still do not know where more than half of the cataloged whales are during any given month other than March and April. There are also a number of calving females that are not sighted after leaving the southeast U.S. (suggesting another nursery around) and a few females that gave birth that were not documented as they matured (suggesting they use none of the four well-studied feeding grounds).
What are other areas that may be important to right whales? Right whales from this population have been seen off Greenland, Iceland, Norway, and the Azores. These areas are mostly far from shore, cover a large geographic area, and experience harsh weather conditions – all of which make them difficult to survey. Despite these logistic difficulties, there are increasing interest in exploring these places in an effort to unravel the enduring mystery about where else right whales go. It should be noted that because survey efforts have been focused both geographically and temporarily on critical habitats during specific times of the year, any whales that are near the coast but at slightly different times of year, or just outside the survey boxes, may not be detected.
Studying right whale behavior is difficult because we only catch short glimpses of their behavior while they are at the surface. We can gain clues about their sub-surface behavior from things such as underwater microphones (hydrophones) and data tags attached to a few whales, as well as from whale dive times. Also, in some areas, whales return to the surface with mud on their heads, indicating that they swam to the ocean’s bottom during that dive.
While at the surface, right whales exhibit a variety of behaviors, including; breaching (jumping out of the water), fluking ( lifting the tail out of the water), nursing, spy hopping (lifting the head out of the water), logging (resting), skim feeding, posturing and participating, in surface active groups (SAGs).
Surface Skim Feeding
Although most of their feeding takes place at depth (as deep as 600-800 feet), right whales occasionally feed at, or just below, the water’s surface. These enormous animals feed on the smallest of prey, tiny animal plankton called copepods. They push their huge open mouths through the water for hours at a time. This behavior is most commonly observed in Cape Cod Bay and may well have been the fodder for some sea monster stories.
Check out this video of Right Whales Skim Feeding!
Right whales are surprisingly flexible considering their girth. When a whale postures, it arches its back, bringing both the flukes and the head out of the water at the same time. The cause of this behavior is unknown, but is often seen when a whale “wakes up” after resting (or “logging”) at the surface.
Surface Active Groups
Surface active groups (SAG’s) are characterized by two or more whales socializing at the surface. Frequent body contact is observed, often with whales, rolling on their sides or backs. They generally involve a single female that vocalizes to attract males. The female typically spends most of the time on her back with her genitals out of the water while the males clasp her from either side with their flippers. Penises are often observed and some SAG’s are believed to play a role in mating. However, many SAG’s do not lead directly to calving because 1) SAG’s have been seen during almost all months, whereas calving occurs primarily from December through March; 2) some SAG’s comprise only males and/or juveniles; and 3) many of the local females are already pregnant.
Frequently Asked Questions
You have questions. We have answers. Our scientists answer some of the most frequently asked questions about North Atlantic right whales.