Española Marine Iguana (Amblyrhynchus cristatus).  This critter swims in the ocean and eats algae.  They can remain under water for an hour or more.  They turn bright red or blue in the breeding season, but the ones on Española Island stay colorful all year.

Galápagos Islands, Ecuador.

Canon Elan IIe camera and 300 f/4 L IS lens with 1.4x teleconverter and Kodak Royal Gold 400 film.