You came to the Caribbean for the beach. So did the wildlife. Throughout the islands, some stretches of sand come with company: two legs or four, from birds to beasts to reptiles.  Some creatures are unexpected, others have earned celebrity status. Some are indigenous to their islands, while others have adapted over centuries to new climes.  Here are some Caribbean beaches where you may have to share your patch of sand – and get a glimpse of a local resident of the wilderness.  The Bahamas: Swimming Pigs  The Caribbean has plenty of marine mammals. The Bahamas famously has marine pigs.  The best-known live on Big Major Cay in the Exumas, now nicknamed…