Species and description

The Insular Cave Rat (Heteropsomys insulans) is an Extinct species of spiny rat

Spiny rat

The spiny rats are a group of hystricognath rodents in the family Echimyidae. They are distributed from central Central America through much of South America. They were also found in the West Indies until the 19th century...

 native to Puerto Rico

Puerto Rico

Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

. The spiny rats are a group of hystricognath rodents in the family Echimyidae. They are distributed from Central America through much of South America. They were also found in the West Indies until the 1800s. Most species have stiff pointed hairs, or a bristly coat of flat flexible spines that allow for protection. Many echimyids can break off their tails when attacked. This action confuses predators long enough for the animal to escape. Unlike lizards, however, the tail of spiny rats does not regenerate. When intact, tails range from less than half the body length to much longer; they may be thinly or densely haired. This technique can obviously be used only once in each individual's lifetime. This species most likely did not do well in conditions of high heat and aridity and are restricted to regions with an abundant source of water. The physical characteristics of spiny rats vary greatly from species to species, from rat-sized to the size of a small cat. Their head and body length is from 4.13 to 18.9 inches (10.5 to 48 centimeters) and a tail length of 0.2 to 16.6 inches (0.5 to 42 centimeters). They weigh from 0.46 to 2.9 pounds (210 to 1,300 grams). In appearance, most species of spiny rat are rat-like, with pointed noses.

Lifestyle

Spiny rats are nocturnal, meaning they are mostly active at night. Most die if they are exposed to heat or dryness. Depending on the species, they live either individually, in small groups, or like the broad-headed spiny rat, in large colonies. The average lifespan is two to four years in the wild. They are generally territorial, meaning they are protective of an area they consider home and claim.

Diet

They were almost exclusively herbivorous. Their diet most likely includeed fruits, nuts, grass, and sugar cane. Several species, including rato de Taquara, eat only bamboo shoots and leaves.

Ancestry

Puerto Rico is the only Greater Antillean island to have lost its entire pre-human Quaternary land mammal fauna. Although both Puerto Rican species are markedly larger than related taxa this group appears to have experienced contemporaneous extinction events across the Caribbean. Of the primary post-Columbian extinction drivers operating in Puerto Rico, massive-scale deforestation for sugarcane wasprobably the leading cause of death.

Fossil

This species may have died out due to introduced carnivorous species and or humans. Echimyid rodents were still present on Puerto Rico approximately 1000 years BP, and probably became extinct following human arrival. Other radiometric studies indicate that small echimyids survived on Cuba and Hispaniola until European arrival. Radiometrically dated archaeological sites and their elevated charcoal levels in sediment cores suggest that extensive anthropogenic forest burning began soon after first human contact with the island. The presence of Heteropsomys in a stratified bone layer at Cueva del Perro cave dated to approximately 5410 BP indicates that these taxa were still extant when Amerindians first settled the island. limited new radiometric data therefore suggest that Puerto Rico’s mammals experienced two waves of extinction, with small-bodied species probably surviving until European arrival, and at least some large-bodied species becoming extinct in protracted pre-Columbian ‘sitzkrieg’-style events rather than ‘blitzkrieg’-style overkill following initial Amerindian colonization. The new last-occurrence dates show that H. insulans was still present on Puerto Rico approximately 1000 years ago.