North Atlantic Right Whales were hunted for at least 800 years, until they became so rare that it was no longer commercially viable to exploit them. Now numbering only in the hundreds, and showing no signs of recovery, Northern right whales are nearly extinct. Some populations have not shown any significant reproduction, even after becoming protected by law.
Today, the North Atlantic right whale is a rarely observed species, but its name derives from an era when they were more frequently sighted, when they swam slowly, close to shore, thus making them an easy target for whalers. Not only did this swimming behaviour make this whale the right one to hunt, but this whale also floats when dead and yielded vast quantities of valuable oil and baleen.
Despite its bulky size, the North Atlantic right whale is able to perform acrobatic acts such as jumping out of the water, known as breaching, violently slapping the water surface with the tail and/or a pectoral fin. Although the purpose of these behaviours is not fully understood, they may be used in communication. Similarly, the range of low frequency groans, moans and belches that the North Atlantic right whale makes are hypothesised to be used to communicate with other individuals, or signal aggression.
Remarkable for massive size, North Atlantic right whales feed chiefly on minute planktonic prey, including large copepods, the size of a grain of rice; krill, a shrimp-like crustacean; tiny planktonic snails and the drifting larval stages of barnacles and other crustaceans. North Atlantic right whales are skim feeders, meaning they consume prey by swimming forward with mouths open, allowing water to flow into the mouth and out through the baleen. Tiny prey are strained from the water as it becomes caught in the fringed baleen, where it is then dislodged by the tongue and swallowed. Although this whale often feeds at or immediately below the ocean surface, the North Atlantic right whale is also believed to sometimes feed close to the bottom, since it has been seen surfacing after a 10 to 20 minute dive with mud on its head.
After feeding at northern latitudes during the summer, the North Atlantic right whale migrates south for winter. Pregnant females head for the inshore calving grounds, whilst the location of the remaining majority of the population is not known. Wherever they move, this is the season at which mating takes place.
North Atlantic right whale females typically first calve at nine to ten years of age, therafter giving birth to a single young every three years. The gestation period lasts for about one year, and following birth, the mother and her young remain close until the calf is weaned at the age of one. During its first year of life the calf learns the location of critical feeding grounds from its mother, which it will continue to visit for the remainder of its life. The female then takes a third year to replenish her energy stores before breeding again.
- * Encyclopedia of Earth. Author: Encyclopedia of Life. 2011. Topic ed. C.Michael Hogan. Ed.-in-chief Cutler J.Cleveland. National Council for Science and the Environment http://www.eoearth.org/article/North_Atlantic_Right_Whale?topic=49540
- * D.W.Macdonald. 2006. The Encyclopedia of Mammals. Oxford University Press, Oxford.
- * C.A.Mayo and M.K.Marx. 1990. Surface foraging behavior of the North Atlantic right whale, Eubalaena glacialis, and associated zooplankton characteristics. Canadian Journal of Zoology, (68), pp. 2214-20.
- ARKive. 2008. North Atlantic right whale (Eubalaena glacialis)
- * A.R.Martin and F.J.Walker. 1997. Sighting of a right whale (Eubalaena glacialis) with calf off S. W. Portugal. Marine Mammal Science 13(1): 139-141.
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