African manatees can grow to about three metres long and weigh up to 500 kg - about as much as a large horse. Their bodies are rounded and smooth, perfectly shaped for drifting slowly through the water. Two small front flippers help them steer, and a wide, flat tail - shaped like a paddle - propels them forward with gentle sweeps.
Manatees are mammals, which means they breathe air just like we do. They surface every few minutes to take a breath, then sink back below. When they are resting, they can stay underwater for up to 20 minutes without coming up. Their nostrils close tightly while they are submerged, then snap open the moment they surface.
Manatees eat only plants - mostly water hyacinths, grasses, and the leaves of mangrove trees floating at the surface. An adult can eat up to 8 per cent of its body weight in plants each day. That is a lot of chewing! Their large lips are very flexible and work like fingers to grab and pull at plants.
Because manatees are shy and quiet, they are easy to miss even when they are nearby. Local fishermen in Guinea-Bissau often know the quiet stretches of river where manatees are most likely to appear. They call them by local names and have observed their habits for generations. Conservation teams work with these communities to make sure manatee habitats stay undisturbed.