Known for very long bridges, vast expanses of blue water, picturesque and historical Key West, and fruity drinks with little umbrellas, the Keys are also home to an unusual assemblage of plant and animal life, both aquatic and terrestrial. Protection and restrictions on development have been in place for a half century, and the result is a tropical paradise that is remarkable for this day and age, and a dream for a biologist, especially one with a boat who likes to go exploring. The focus is on the lower Keys, especially Big Pine Key, the least developed portion of the island chain.