Dugong dugong
Scientific Name:-
Dugong dugongCommon Name:-
Dugong
Malayalam Name:-
Kadal Pasu
Category:-
Mammals
Status:-
Classified as "Vulnerable” by the IUCN and listed in Appendix I of CITES and Conservation of Migratory Species of Wild Animals (CMS). Listed in Schedule I of Indian (Wildlife) Protection Act.
Description:-
The dugong's body is large with a cylindrical shape that tapers at both ends. It has thick, smooth skin that is a pale cream colour at birth, but darkens dorsally and laterally to brownish-to-dark-grey with age. The colour of a dugong can change due to the growth of algae on the skin. The body is sparsely covered in short hair, a common feature among sirenians which may allow for tactile interpretation of their environment. These hairs are most developed around the mouth, which has a large horseshoe shaped upper lip forming a highly mobile muzzle. This muscular upper lip aids the dugong in foraging. The dugong's tail flukes and flippers are similar to those of dolphins. These flukes are raised up and down in long strokes to move the animal forward, and can be twisted to turn. The forelimbs are paddle-like flippers which aid in turning and slowing. The dugong lacks nails on its flippers, which are only 15% of a dugong's body length. The tail has deep notches. The eyes are small and the ears, which lack pinna, are located on the sides of their head. The nostrils are located on top of the head and can be closed using valves. Dugongs have two teats, one located behind each flipper.
Fully grown, they may be three metres long and weigh 400 kilograms. Dugongs swim by moving their broad whale-like tail in an up and down motion, and by use of their two flippers. They come to the surface to breathe through nostrils near the top of their snouts. Dugongs' only hairs are the bristles near the mouth.
Threats:-
The dugong’s historic distribution is believed to have been broadly coincident with the tropical Indo–Pacific distribution of its food plants, the phanerogamous seagrasses of the families. The disappearance of sea grass beds is one of the reasons for its decline besides the impacts of fishing.
Remark:-
There are no recent records of this species from Kerala coast.
Habitat:-
The dugong is the only herbivorous mammal that is strictly marine and is the only extant species in the Family Dugongidae. The dugong has a large range that spans at least 37 countries and territories and includes tropical and subtropical coastal and island waters. They generally frequent coastal waters. Major concentrations tend to occur in wide shallow protected bays, wide shallow mangrove channels and in the lee of large inshore islands.
References:-
De Silva, P. (1987). Cetaceans (whales, dolphins and porpoises) recorded off Sri Lanka, India, from the Arabian Sea and Gulf, Gulf of Aden and from the Red Sea.
Jayasankar, P. and Anoop, B. 2010. Identification of Marine Mammals of India. Narendra Publishing House, Delhi.
Jefferson, T.A., Leatherwood, S. and Webber, M.A. 1993. FAO Species identification guide. Marine Mammals of the World: UNEP / FAO, Rome, 320 pp.
Jefferson, T. A., M. A. Webber and R. L. Pitman. (2008). Marine mammals of the world. Academic Press, Amsterdam.
Marsh, H. 2008. Dugong dugon. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 26 September 2014.
Sathasivam, K. 2004.Marine Mammals of India. University Press, Hyderabad.
Vivekanandan, E. and Jeyabaskaran, R. 2012. Marine Mammal Species of India. Central Marine Fisheries Research Institute, Kochi, 228pp.