True's Beaked Whale
The True's Beaked Whale (Mesoplodon mirus) is a medium sized whale in the Mesoplodont genus. The common name is in reference to Frederick W. True, a curator at the United States National Museum (now the Smithsonian). There are two distinct populations in the Atlantic and Indian ocean (this species is absent in the tropics) which may be separate subspecies.
This whale has a normal Mesoplodont body, except that it is rotund in the middle and tapering towards the ends. The two distinctive teeth on the males are small and set on the very end of the beak. The melon is rather bulbous, and leads into a short beak. There is a crease behind the blowhole, and a sharp dorsal ridge on the back near the dorsal fin. The coloration is gray to brownish gray on the back which is lighter below, and notably darker on the "lips", around the eye, and near the dorsal fin. There is sometimes a dark blaze between the head and dorsal fin as well. One female in the Southern Hemisphere was bluish black with a white area between the dorsal fin and tail as well as a light gray jaw and throat, as well as black speckling. Scars from fighting and cookiecutter sharks are present on males. This species reaches around 5.3 meters (17 feet 6 inches) with the females weighing 1400 kilograms (3000 pounds) and the males weighing 1010 kilograms (2200 pounds). They are around 2.2 meters (7 feet) long when born.
They have been seen in small groups, and are believed to be squid eaters. It is believed that when a whale is injured, another whale stays with it to nurse it. Other than that, little else is known.
Population and distribution
One population, possibly genetically distinct, lives in the Northern Hemisphere and has stranded from Nova Scotia in the western Atlantic to Ireland in the eastern Atlantic and as far south as Florida, the Bahamas, and Canary Islands. Another population lives in the Southern Hemisphere and has stranded in South Africa and Australia. The species does not inhabit the Southern Atlantic or Northern Indian Ocean, and appears to avoid tropical waters. No population estimates have been established, but it is believed to be one of the rarest species of whale.
This species has not been hunted and has not been a victim of fishing nets.
- ^ Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. & Pitman, R.L. (2008). Mesoplodon mirus. 2008 IUCN Red List of Threatened Species. IUCN 2008. Retrieved on 24 March 2009. Database entry includes a brief justification of why this species is of data deficient.
- Encyclopedia of Marine Mammals. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002. ISBN 0-12-551340-2
- Sea Mammals of the World. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002. ISBN 0-7136-6334-0
- Rare species found dead