Florida manatees Trichechus manatus latirostris actively consume the sponge Chondrilla caribensis

Abstract

The Florida manatee (Trichechus manatus latirostris Linnaeus 1758) actively selects and consumes the “chicken-liver” sponge Chondrilla caribensis. Manatees ate over 10% of C. caribensis on a sample dock, mostly from pylons that received no direct sunlight. Since manatees reportedly eat mostly seagrasses and algae, it was thought that the chlorophyll-a content of the symbiotic cyanobacteria in C. caribensis might be correlated to the amount eaten; however the correlation was not significant (P > 0.05). C. caribensis has variable chemical defenses and round spherasters (spicules), but these do not appear to be effective deterrents to predation by manatees. This is the first direct evidence that manatees actively seek out and consume a sponge.