Juvenile rhesus macaques play above water. Source: Alyssa Arre, used with permission. The island of Cayo Santiago off the east coast of Puerto Rico is home to an unusual population of rhesus macaques.

Juvenile rhesus macaques play above water. Source: Alyssa Arre, used with permission. The island of Cayo Santiago off the east coast of Puerto Rico is home to an unusual population of rhesus macaques.

As the youngster gains confidence, he’s beguiled by the antics of other macaques taking turns to jump into the cooling waters, and begins to scale a column towards an impromptu diving board.“ Climbing ...