West Indian manatee
Trichechus manatus

The West Indian manatee (Trichechus manatus) shares with the other two species of the genus Trichechus an immediately recognizable body plan. Each morphological trait is a direct response to the constraints of its environment.

Fusiform body and rounded caudal fin

The body is massive, without a marked constriction between the trunk and tail. The rounded paddle-shaped caudal fin is the most reliable visual criterion to distinguish the manatee from the dugong (Dugong dugon), whose tail is notched like a dolphin’s. At the surface, this paddle often breaks before the head, helping identify the animal even in poor visibility.

Vibrissae and tactile sensory system

The snout bears several hundred thick vibrissae distributed across the upper lip. These tactile bristles are individually innervated: they detect texture, shape and position of aquatic plants with precision comparable to human fingers (MNHN). Underwater, a feeding manatee uses its vibrissae as much as its often poor vision in turbid estuarine waters.

Prehensile lip

The mobile, cleft upper lip is a full prehensile organ. Each half moves independently to grasp, twist and tear seagrass. This lip also plays a role in tactile communication between individuals, especially between a female and her calf.

Digestive tract and strict herbivory

The digestive tract measures about 40 meters long, with a voluminous caecum where bacteria ferment plant cellulose. This post-gastric fermentation is slow: the manatee spends 6 to 8 hours per day feeding to meet its energy needs. Biologically, it is closer to a rhinoceros than a ruminant, despite the popular nickname “sea cow” (MNHN).

The species Trichechus manatus comprises two recognized subspecies. Confusion between them is common in mainstream media, yet the distinction has direct consequences for conservation strategies.

West Indian manatee (Trichechus manatus manatus)

T. m. manatus occupies Caribbean coasts from Mexico and the Antilles to northeastern Brazil. Its population is fragmented, poorly surveyed, and several insular subpopulations are considered functionally extinct. This is the subspecies targeted by the Guadeloupe reintroduction program.

Florida manatee (Trichechus manatus latirostris)

T. m. latirostris is restricted to the coastal waters of the southeastern United States, mainly Florida. Its population is better documented thanks to decades of monitoring by the USGS and the Florida Fish and Wildlife Conservation Commission. Lessons from this monitoring, especially the impact of propeller collisions, are directly applicable to managing T. m. manatus.

Comparative table

Why the subspecific distinction matters

An individual of T. m. latirostris cannot replace one of T. m. manatus in a reintroduction program: behavioral, thermal and dietary adaptations differ. The European Breeding Program (EEP) for the West Indian manatee works exclusively with the manatus subspecies, limiting the available breeding pool.

Observing a manatee in its natural habitat requires patience and careful reading of the environment. Most encounters are brief and partial.

Surface silhouette

At the surface the manatee rarely exposes more than its rounded back and nostrils. The complete absence of a dorsal fin is an immediate clue. Color is gray-brown, sometimes mottled with algae or scars. The paddle-shaped caudal fin may surface during dives.

Breathing behavior

At rest the manatee surfaces every 3 to 5 minutes. Breathing is discreet: no visible blow at distance, unlike cetaceans. A brief nasal hiss may sometimes be heard from a kayak. During intense activity, surfacings become more frequent and rapid.

Behavioral traces and indirect signs

When visibility is poor, indirect signs are often more useful than direct observation. A seagrass bed grazed in regular strips, slight localized turbidity on the bottom, or small columns of bubbles rising from the seabed indicate recent feeding activity. These traces persist for several hours after the animal has passed.

Possible confusions

The dugong (Dugong dugon) is absent from the Caribbean: confusion is geographically impossible on site. However, a green turtle (Chelonia mydas) grazing seagrass can, from the surface, be mistaken for a manatee by an unwary observer. Head shape and the absence of visible forelimbs on the manatee allow quick differentiation.

The distribution of the West Indian manatee is not uniform across the Caribbean. Understanding why observation spots concentrate in certain areas and are absent from others is essential for planning field trips.

Seagrass beds, estuaries and freshwater sources

The manatee uses three complementary habitat types. Coastal seagrass beds are its main food source. Estuaries and lagoons provide calm, shallow waters favorable for calving and nursing. Freshwater sources (rivers, springs) are visited for drinking and, in Florida, for thermoregulation. Degradation of any one of these three habitats is enough to render an area unsuitable for a resident population.

The distribution “gap” in the Lesser Antilles

The Lesser Antilles show a striking gap in the species’ distribution. The islands are small, coastal shelves narrow, seagrass beds fragmented, and historical hunting pressure intense. This “gap” is not natural: resident populations existed on several French islands until the 20th century. Their disappearance is the direct result of overexploitation and coastal habitat degradation.

Historical and current presence in Guadeloupe and Martinique

In Guadeloupe, manatees were present in the Grand Cul-de-Sac Marin until the 1990s. Current sightings involve vagrant individuals, probably from Trinidad or Venezuela populations (OFB Antilles). The situation in Martinique is comparable: recent observations are rare and unconfirmed as resident. Both territories are nevertheless at the heart of the reintroduction project led by the MNHN and OFB.

Thermal tolerance

The West Indian manatee tolerates cold less well than its Florida cousin. Below 20 °C it shows signs of thermal stress. This constraint explains why the species does not spontaneously colonize cooler waters and why warm-water sources are critical gathering points in winter in the northern parts of its range.

In Guadeloupe and Martinique the West Indian manatee benefits from protected-species status under the ministerial order of 27 July 1995 listing protected marine mammals on national territory. Any intentional disturbance, capture, injury or destruction is subject to criminal penalties.

Minimum distances and contact prohibitions

OFB Antilles recommends maintaining a minimum distance of 50 meters from a motorized boat and not approaching closer than 10 meters while swimming or kayaking. Voluntary physical contact is strictly prohibited. Beyond regulations, direct contact can transmit pathogens to an animal whose immune system is not adapted to human flora.

Marine protected areas in Guadeloupe and Martinique

The Parc National de la Guadeloupe and the Réserve Naturelle du Grand Cul-de-Sac Marin have specific regulations on navigation and nautical activities. In Martinique, the Réserve Naturelle Régionale de la Caravelle controls access to certain coastal zones. Approved local operators know the current zoning: consult them before any outing.

Behaviors to avoid

Several behaviors are particularly harmful even without direct contact. Low-speed engine noise in shallow areas masks acoustic signals used by females to locate their calves. Artificial feeding (offering food) alters natural behavior and creates a dangerous association between the animal and boats. Swimming actively toward a manatee, even slowly, is perceived as a threat and generates measurable stress on the animal’s heart rate. In the reintroduction program, any negative conditioning of released individuals directly compromises success.

The IUCN classifies Trichechus manatus as vulnerable worldwide (IUCN, 2022). For the T. m. manatus subspecies in the French Lesser Antilles the situation is more critical: resident populations have virtually disappeared.

Main threats

Three threats dominate. Collisions with boat propellers cause direct mortality and chronic injuries: propeller scars are in fact used as individual markers in photo-ID for population censuses (MNHN). Accidental capture in fishing nets (gillnets, traps) is the second cause of mortality. Finally, degradation of seagrass beds by eutrophication, anchor damage and coastal development reduces habitat carrying capacity.

European Breeding Program (EEP)

The European Breeding Program (EEP) for Trichechus manatus manatus coordinates captive breeding in several European zoos, including the Parc Zoologique de Paris (Zoo de Vincennes). The goal is not ex-situ conservation per se but building a breeding pool to supply reintroduction programs. The number of available individuals remains limited, constraining release rates.

The Guadeloupe reintroduction project

The MNHN and OFB lead a manatee reintroduction project in Guadeloupe centered on the Grand Cul-de-Sac Marin. The project includes several stages: assessment of residual seagrass quality, social-acceptability study among fishing and boating communities, then gradual releases of EEP individuals. Concrete obstacles exist: Guadeloupe’s seagrass quality has declined since the 1990s, and coexistence with intensive nautical activities remains an unresolved challenge. Post-release monitoring includes satellite tags and photo-ID protocols to evaluate integration into the new environment.

The West Indian manatee has traversed Caribbean human history for millennia, between myth, exploitation and late protection attempts.

The mermaid myth

Early European navigators associated manatees with the sirens of ancient tales. Christopher Columbus noted in 1493 having sighted three “mermaids” that were not very attractive off Hispaniola: he was almost certainly describing manatees. The confusion is explained by the nursing posture of the female, holding her calf against her chest with her pectoral flippers, and by the animal’s vertical silhouette at the surface. Biologically, nothing links the manatee to a human, but the perceived resemblance from a ship’s deck in poor visibility is documented.

Historical hunting and population collapse

Manatee meat was highly prized in the Antilles and the animal was actively hunted by Amerindian then colonial populations. Harpoon and net hunting caused rapid collapse of insular populations from the 17th century onward. Several islands lost their resident populations before the end of the 19th century. Legal hunting bans came too late to reverse the trend in most of the Lesser Antilles.

Place in Amerindian and Creole cultures

For Arawak and Carib peoples the manatee occupied a place in diet and cosmology. Some Creole communities on the coasts of Guyana and Trinidad retain oral traditions linked to the animal. Its name in Guadeloupean Creole, lamantin, is borrowed directly from Carib manati.

Steller’s sea cow: a warning

Steller’s sea cow (Hydrodamalis gigas), the giant sirenian of the cold North Pacific, was exterminated in less than 27 years after its discovery by Europeans in 1741. Its extinction illustrates the extreme vulnerability of sirenians to intensive hunting. The West Indian manatee is not immune to a comparable scenario if current pressures are not reduced.