Food-handling ability and feeding-cycle length of manatees feeding on several species of aquatic plants

Food-handling ability was examined in Florida manatees (Trichechus manatus latirostris) feeding on different species of aquatic plants during controll ed feeding trials. Subjects were presented with freshwater (Hydrilla vertic illata, Myriophyllum spicatum, and Vallisneria americana) and marine specie s (Syringodium filiforme and Thalassia testudinum) of aquatic plants. Food handling was quantified by measuring length of cyclic movements (or feeding cycles) of perioral bristles that manatees use to introduce food into the mouth. Mean feeding-cycle lengths varied, depending on body size of the sub ject and species of plant being consumed. Rates of food introduction derive d from mean feeding-cycle lengths were similar to chewing rates reported by other researchers. Manatees consumed plants with tubular stems and numerou s branches faster than plants with flat blades. Food-handling time using pe rioral bristles differed, depending on the species of plants consumed and w as reflected in the mean feeding-cycle length.