Alex Mustard / A Florida manatee (Trichechus manatus latirostrus) head portrait in Three Sisters Spring. Crystal River, Florida, USA. February 2010

Alex Mustard / A group of Florida manatees (Trichechus manatus latirostrus) sleeping in the afternoon at Three Sisters Spring. Crystal River, Florida, USA. Manatees sleep on the bottom of the spring, floating up per...

Alex Mustard / A group of Florida manatees (Trichechus manatus latirostrus) sleeping in the afternoon at Three Sisters Spring. Manatees sleep on the bottom of this shallow spring, occasionally rising to the surface...

Alex Mustard / Two Florida manatee (Trichechus manatus latirostrus) surfacing to breathe, in morning light. Three Sisters Spring, Crystal River, Florida. USA. January

Alex Mustard / Bluegill sunfish (Lepomis macrochirus) sheltering beneath a Florida manatee (Trichechus manatus latirostrus). Crystal River, Florida, USA.

Alex Mustard / Young Florida manatee (Trichechus manatus latirostrus) stays warm in a freshwater spring in winter, at dawn. Three Sisters Spring, Crystal River, Florida, USA. January

Alex Mustard / Florida manatee (Trichechus manatus latirostrus) swimming under trees in Three Sisters Spring, Crystal River, Florida, USA. January

Alex Mustard / Young Florida manatee (Trichechus manatus latirostrus) portrait, Three Sisters Spring, Crystal River, Florida, USA. February 2010

Alex Mustard / A Florida manatee (Trichechus manatus latirostrus) close up head /nostrils portrait in Three Sisters Spring. Crystal River, Florida, USA. February 2010

Luciano Candisani / Antillean Manatee (Trichechus manatus manatus) in coastal shallow waters, Brazil

Chris Newbert / West Indian Manatee (Trichechus manatus) floating at water surface, Florida

Norbert Wu / West Indian Manatee (Trichechus manatus), Crystal River, Florida