West and Central Africa contains a variety of suitable habitats for manatees ranging from large and small rivers, coastal estuaries, freshwater and saltwater lagoons, shallow quiet coastal bays, lakes and reservoirs. Like T. manatus, T. senegalensis inhabits practically every accessible habitat (Hartman 1979, Powell et al. 1981, Rathbun et al. 1983, Powell and Rathbun 1984). They were observed or recorded from coastal areas, estuarine lagoons, large rivers that range from brackish to fresh water, freshwater lakes and the extreme upper reaches of rivers above cataracts. In general, their habitat requirements seem to be similar to T. manatus and require sheltered water with access to food and freshwater (Powell and Rathbun 1984). They may transit areas of unsheltered coast, but they are usually rare in these areas.

Optimal coastal habitats for manatees, based on the movements of radio-tagged manatees in Côte d’Ivoire and the number of reported sightings from other areas were: a. coastal lagoons with abundant growth of mangrove or emergent herbaceous growth; b. estuarine areas of larger rivers with abundant mangrove (Rhizophora racemosa) in the lower reaches and lined with grasses, particularly Vossia and Echinochloa further upriver; c. shallow (<3 m depth) and protected coastal areas with fringing mangroves or marine macrophytes, particularly Ruppia, Halodule or Cymodocea. In riverine habitats that have major fluctuations in flow rates and water levels, manatees seem to prefer those areas that have access to deep pools or connecting lakes for refuge during the dry season and seasonally flood into swamps or forests with abundant grasses and sedges, particularly Vossia, Echinochloa and Phragmites.

T. senegalensis are mostly solitary, with mothers and calves the principal social unit. Manatees will often rest together in loose, small groups of two to six individuals. They feed principally at night and travel in the late afternoon and at night. They usually rest during the day in water that is 1–2 m deep and sometimes in the middle of a watercourse or hidden in mangrove roots or under natant vegetation. They make little disturbance while swimming. These latter behaviors may be due to hunting pressures.

Manatees feed primarily on vegetation including: Vossia sp., Eichornia crassipes, Polygonum sp., Cymodocea nodosa, Ceratophyllum demersum, Azolla sp., Echinochloa sp., Lemna sp., Myriophyllum sp., Pistia stratioties, Rhizophora racemsoa, and Halodule sp. In Senegal (Powell, unpub. data) and Sierra Leone (Reeves et al. 1988), manatees are also known to eat small fish captured in fishermen’s nets. In Senegal and The Gambia, shell remains of mollusks have also been found in their stomachs.

Manatees can travel freely from salt to freshwater. They appear to prefer estuarine areas where there is little disturbance and the waters are shallow and calm. They can be found in marine habitats where there are relatively calm water and a source of freshwater. For example, in Senegal, The Gambia, and Guinea-Bissau, manatees are attracted to freshwater seeps or springs that are found in marine habitats (Powell 1990).