Mammals
The richness of mammals in Puerto Rico, like many other islands, is low relative to mainland regions. The present-day native terrestrial mammal fauna of Puerto Rico is composed of only 13 species, all of which are bats. Eighteen marine mammals, including manatees, dolphins and whales, occur in Puerto Rico. Fossil records show the existence of one shrew (Puerto Rican shrew, Nesophontes edithae), one sloth (Puerto Rican Sloth), three additional leaf-nosed bats (Macrotus waterhousii, Monophyllus plethodon, and Phyllonycteris major), and five rodents (one giant hutia: Elasmodontomys obliquus, one hutia: Isolobodon portoricensis and three spiny rats: Heteropsomys antillensis, Heteropsomys insulans, and Puertoricomys corozalus). Woods suggests a reason for their extinction: "Taxa evolving in isolation on oceanic islands without competition or predators may not be able to adapt to rapidly changing conditions, such as the extensive climatic fluctuations of the Ice Ages or sudden competition or predation from introduced animals".
Other terrestrial mammals have been introduced throughout the history of Puerto Rico. Indigenous settlers first introduced dogs and guinea pigs from South or Central America. Afterwards, Taínos introduced hutias as a food source from Hispaniola. When the Spanish colonized the island in the early 16th century, they introduced domesticated animals such as dogs, cats, goats, pigs, cattle, horses, and donkeys. Other species such as Black Rats (Rattus rattus), Norway Rats (Rattus norvegicus) and house mice (Mus sp.) have been unintentionally introduced as stowaways, possibly since Christopher Columbus's arrival in 1493. More recently, species have been introduced as a means of biological pest control. For example, the Small Asian Mongoose (Herpestes javanicus) was introduced in the 19th century to control the damage caused by rats in sugar cane plantations. The introduction was a failure: the mongoose failed to control the rat population and instead contributed to the decline of native fauna such as the Yellow-shouldered Blackbird and possibly the Elfin-woods Warbler.
As part of a study on adaptation, 57 Rhesus Macaques (Macaca mulatta) were introduced to the island of Desecheo and other southern off-shore islands and cays in 1967. Prior to the introduction, Desecheo was the largest nesting colony of the Brown Booby, but mainly as a result of egg predation by the introduced macaques, no bird species presently nests in the island. Efforts to trap and remove the species have been unsuccessful and it has expanded its range to southwestern Puerto Rico. Other primates also have established populations in Puerto Rico. As a result of vandalism, 107 Squirrel monkeys escaped from a research station at Sabana Seca in the late 1970s. The latest estimate for this population is 35 individuals.
Arguably the most famous of aquatic mammals occurring in Puerto Rican waters is the Antillean Manatee (Trichechus manatus manatus) which is listed as vulnerable by the IUCN. The archipelago's waters are one of the species' main breeding areas. Manatees gathered local media attention when a two-month manatee nicknamed Moisés was rescued and raised for 27 months by the Caribbean Stranding Network (CSN). Moisés was the first successful release of an orphaned, captive-raised manatee to the marine environment in the Caribbean. The animal became a Puerto Rican cultural, as well as scientific, icon when Tony Croatto wrote a song titled "Moisés". A municipality of Puerto Rico, Manatí is believed to be named after the species.
Puerto Rico's waters are also an important breeding site for the Humpback whale during the Northern Hemisphere's winter. Humpback whale watching is a popular tourist attraction in the municipality of Rincón in western Puerto Rico.
Read more about this topic: Fauna Of Puerto Rico