Manatees and Dugongs

Contents:


Current Status
Rating:
Population:
Threats:

IUCN Red List: inunguis - VU A1cd manatus - VU A2d manatus manatus - VU A1cd, C2a manatus latirostris - VU A2d senegalensis - VU A1cd Dugong dugon - VU A1cd

The prospect for these mammals is very bleak. One species has already been driven to extinction by man in the mid 1700's. The remaining species, although protected in most parts of the world, are slowly dwindling in number due to habitat destruction. Recently a killer pneumonia-like disease has been spreading through the manatee population off Florida's coast, taking an unusually high toll.

Description

Sirenians have small heads and massive bodies. Their hind limbs are fused to form a horizontal paddle. The fore limbs have formed flippers, with only rudimentary nails to indicate the prior existence of "fingers".

The upper lip is large and fleshy and covered with sensitive whiskers.

Manatees have a rounded tail paddle, whereas Dugongs have a notched tail paddle.

Classification

Manatees and dugongs belong to the order Sirenia. This order is divided into two families, the Trichechidae (manatees) and the Dugongidae (dugongs). They are believed to be related to elephants and are thought to have evolved from land mammals which returned to the oceans.

The Trichechidae have only one species, which is divided into three distinct subspecies:

  1. Trichechus manatus (American manatee),
  2. Trichechus manatus manatus (Antillean manatee),
  3. Trichechus manatus latirostris (Florida manatee), and
  4. Trichechus inungius (Amazonian manatee),
  5. Trichechus senegalensis (African manatee)

The Dugongidae also has only one surviving species, which is also divided into three subspecies:

  1. Dugong dugong dugong (Mozambique - Philippines)
  2. Dugong dugong australe (Australian dugong), and
  3. Dugong dugong hemprichi (Red Sea)

The second member of the dugong family was Steller's sea cow, which has been hunted to extinction by humans.

Behaviour

Sirenians are gentle vegetarians, which live exclusively on marine or freshwater plants, seaweed and algae. They are also excellent parents, staying with the young for the first two years. They are also strictly monogamous, once a mate is found.

Their eyesight is poor, but hearing good and sense of smell excellent. The sensitive whiskers on the upper lip are used to sort and collect their food.

The Florida manatee is the best known of the Sirenians, because it has become quite used to the presence of people. This is sometimes unfortunate, since they are frequently injured, often fatally, by motorboat propellors.

Very little is known about the dugongs, since they are shy and not often seen. Recently, a biologist, Professor Paul Anderson, discovered that the male dugongs appear to be quite territorial during mating season, defending a feeding area to attract females. The males have a bizarre mating ritual during this time, in which they attempt to support as much of their bulk as possible above water, in a curious sitting position. These "sit-up" contests often result in the males literally falling over backwards in their attempts to show off their prowess!

Relationship with Man

This name is derived from the sirens of Greek mythology, who lured unwary sailors to their deaths by their songs of seduction. It is thought that early sightings of manatees or dugongs inspired the originaly myths of mermaids.

World Distribution senegalensis - Angola, Benin (ex?), Cameroon, Chad, Congo, Cote d'Ivoire, Equatorial Guinea, Gabon, Gambia, Ghana, Guinea (?), Guinea-Bissau (?), Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, Togo, Zaire IUCN - Angola, Benin (ex?), Cameroon, Chad, Congo, Cote d'Ivoire, Equatorial Guinea, Gabon, Gambia, Ghana, Guinea (?), Guinea-Bissau (?), Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, Togo, Zaire inunguis - Brazil, Colombia, Ecuador, Peru, Venezuela IUCN - Brazil, Colombia, Ecuador, Peru, Venezuela manatus - Antigua and Barbuda (ex), Bahamas, Belize, Brazil, Colombia, Costa Rica, Cuba, Dominican Republic, French Guiana, Guadeloupe (ex), Guatemala, Guyana, Haiti, Honduras, Jamaica, Martinique (ex), Mexico, Netherlands Antilles, Nicaragua, Panama, Puerto Rico, Suriname, Trinidad and Tobago, USA, Venezuela, Virgin Islands (British) (ex), Virgin Islands (US) (ex) IUCN - Antigua and Barbuda (ex), Bahamas, Belize, Brazil, Colombia, Costa Rica, Cuba, Dominican Republic, French Guiana, Guadeloupe (ex), Guatemala, Guyana, Haiti, Honduras, Jamaica, Martinique (ex), Mexico, Netherlands Antilles, Nicaragua, Panama, Puerto Rico, Suriname, Trinidad and Tobago, USA, Venezuela, Virgin Islands (British) (ex), Virgin Islands (US) (ex) dugong - Australia, Bahrain, Bangladesh, Brunei (?), Cambodia, China, Comoros (?), Djibouti, Egypt, Eritrea, Federated States of Micronesia, Guam, India, Indonesia, Iran, Iraq, Israel, Japan, Jordan, Kenya, Kuwait, Madagascar, Malaysia, Maldives (ex), Mauritius, Mozambique, Myanmar, New Caledonia, North Korea, Oman, Pakistan (?), Palau, Papua New Guinea, Philippines, Saudi Arabia, Singapore, Solomon Islands, Somalia, South Africa, South Korea, Sri Lanka, Sudan, Taiwan, Tanzania, Thailand, United Arab Emirates, Vanuatu, Viet Nam, Yemen IUCN - Australia, Bahrain, Bangladesh, Brunei (?), Cambodia, China, Comoros (?), Djibouti, Egypt, Eritrea, Federated States of Micronesia, Guam, India, Indonesia, Iran, Iraq, Israel, Japan, Jordan, Kenya, Kuwait, Madagascar, Malaysia, Maldives (ex), Mauritius, Mozambique, Myanmar, New Caledonia, North Korea, Oman, Pakistan (?), Palau, Papua New Guinea, Philippines, Saudi Arabia, Singapore, Solomon Islands, Somalia, South Africa, South Korea, Sri Lanka, Sudan, Taiwan, Tanzania, Thailand, United Arab Emirates, Vanuatu, Viet Nam, Yemen manatus manatus - Belize, Brazil, Colombia, Costa Rica, Cuba, Dominican Republic, French Guiana, Guatemala, Guyana, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Panama, Puerto Rico, Suriname, Venezuela latirostris - USA

Organisations

Sirenian Specialist Group of IUCN

Save the Manatee Club
500 N. Maitland Ave
Suite 210
Maitland
FL 32751
(includes an adoption program)

Pictures

Other websites

http://www.webcom.com/wiwcwww/volunteers/Sept98/

References