El Yunque National Forest

Common Puerto Rican Brown Tarantula, Puerto Rican Pygmy Tarantula (Eng.), Tarantula (Sp.), Araña Pelúa (Puerto Rican folkloric name), Cyrtopholis portoricae (Sci.), Native, Puerto Rico.

Information compiled by Alan Mowbray, Interpretive Media Writer, EYNF/LEF

General Information:
Spiders in the suborder Mygalomorphae, more commonly known as Tarantulas are among the largest known arachnids, with some species having legs as long as an adult male human’s spread hand!
Like most spiders, Tarantulas produce silk, but do not use it to make webs. Instead they use it to line their lairs and create egg-sacs.

Description:
The Common Puerto Rican Brown Tarantula (Cyrtopholis portoricae) is a medium-sized terrestrial arachnid, typically no more than 3 to 5 inches (7.6 to 12.7 centimeters) in length (including leg span), having a dark brown body covered with short, shiny hairs called setae. Typical weight is approximately 1 to 1.5 ounces (28 to 42 grams). Females are slightly larger than males and tend to live longer. Besides its normal “setae” hair covering its body Cyrtopholis portoricae has a dense covering of “urticating” (irritating) fine barbed hairs on the abdomen that can be launched into the air by vibrating the back legs against the abdomen as a protection against predators. These hairs can cause irritation to the eyes, nose and skin of humans.

Habits:
The Common Puerto Rican Brown Tarantula is a nocturnal predator, killing its prey by injecting venom with its long, black fangs. It typically waits patiently at the entrance to its burrow to ambush prey. Almost blind, it has sensitive hairs that enable it to sense the vibration caused by movement to determine the size and location of a potential victim. Its prey consists of insects and occasionally small animals such as frogs. After consuming its prey Cyrtopholis portoricae cleans itself by rubbing its legs together and over its body to remove scraps and debris, finishing its clean-up by licking its legs and the tips of its pedipalps (short, leg-like appendages near the mouth parts.) The Common Puerto Rican Brown Tarantula female may live up to 5 years, while the male typically survives only 1 to 1.5 years. After a short gestation period, impregnated females will deposit 50 to 100 eggs in a silken egg-sac and guard it for up to 7 weeks. The spiderlings remain in the nest for a brief time after hatching and then disperse.

Habitat:
Cyrtopholis portoricae live in burrows that they dig by themselves, occasionally using holes abandoned by rodent or other small burrowing animals. Burrow entrances are lined with silk for concealment.

Where to look for this animal in the EYNF:
Since the tarantula is nocturnal, only their burrows are visible near forest trails during the day. However, during late summer (September through October) males can be seen wandering (occasionally crossing trails) during daylight hours. in search of female mates.

Additional Information:
Biologist
USDA Forest Service
El Yunque National Forest
HC-01 Box 13490
Rio Grande, PR 00745
787 888 1810