SCIENTIFIC CLASSIFICATION

DESCRIPTION

Manatees are gentle and slow-moving. Most of their time is spent eating, resting, and in travel. Manatees feed primarily on sea grasses and sometimes, on small invertebrates. They can consume 10-15% of their body weight daily in vegetation.

The West Indian sea cow has evolved in areas with no natural predators and as a result the members of this species have had no need to develop complex behaviours for predator avoidance. It is believed they can live 60 years or more.

The Florida manatee (Trichechus manatus latirostris) is a subspecies of the West Indian manatee. The other subspecies of the West Indian manatee is sometimes referred to as a Caribbean/Antillean manatee (Trichechus manatus manatus).

The areas inhabited by this species have fairly constant temperatures year-round and an abundant food source, and without the need for group foraging techniques or group defence, this species is largely solitary, occasionally forming loose aggregations.

Manatees are not territorial and do not observe any social hierarchy. Most groups are temporary associations, without regard to sex or age. One exception is herds of juvenile males, which are temporary groups that arise from the exclusion of such individuals from reproductive activities. In addition temporary mating herds develop when a female is in oestrus (estrus).

Manatees use their tail to propel themselves forward and are surprisingly agile in the water. They are capable of complex manoeuvring including somersaults, rolls, and swimming upside-down. They are active day and night, resting for several hours at a time near the surface of the water or at the bottom. While resting on the bottom, they rise to the surface to breathe every few minutes.

Manatees use various forms of communication in the water. Individuals rub themselves against hard surfaces, possibly secreting a scent to convey information about the reproductive state of the resident females. Manatees also have an acute ability to hear and squeals are often used to keep contact between a mother and calf. Vision seems to be the preferred method of navigation.

Gestation period lasts from 12 to 14 months. Normally, one calf is born, although on rare occasions two have been recorded, every two to five years. Mothers nurse their young for 1 to 2 years, so a calf may remain dependent on its mother during that time even though the young are born with molars and premolars, which allow them to consume sea grass within the first 3 weeks of birth. The family unit consists of mother and calf, which remain together for up to 2 years. Males usually contribute no parental care to the calf.

RANGE AND POPULATION

Although their range is quite large, manatees today exist only in a few small, isolated populations. They once were widespread in rivers and along coasts in their range, but they were hunted extensively in the 18th and 19th centuries. Coastal development has further reduced their populations.

The destruction of the swampland habitat for development and agricultural uses has annihilated local populations. Now, less than a hundred manatees live in the Nariva Swamp, a protected area.

THREATS

CONSERVATION MEASURES