The marine iguanas of the Galapagos are unique to the world of iguanas.  They are the only known iguanas to dive into the ocean to feed on the algae encrusted rocks off the coast of the islands. When they out onto the beach the crowd together to get warm as well as spending time expelling the salt from their system by blowing it out through their nose.  The marine iguanas are smaller than the land iguanas and much less colorful.  They can stay submerged for up to an hour.