During this dry season 50% of adult females and 64% of adult male are reproductive. Females are reproductive between April to August during the dry season. Reproduction and Development īoa constrictor occidentalis reproduction is strongly seasonal within both sexes. It ambushes prey, grasping the prey using its mouth and large teeth, proceeding to wrap its coils around the body of the prey, exerting high amounts of external pressure that stop blood flow to the brain, quickly killing the prey. As per its species, the Boa constrictor occidentalis kills prey by constriction. This subspecies is very active at night, climbing on trees to ambush prey. Boa constrictor occidentalis enjoy soaking in water and as such live in wetlands and near bodies of water such as streams, ponds, rivers, etc.īoa constrictor occidentalis is an opportunistic hunter, feeding on small animals, birds, and rodents. They are known to be a very docile but can become very aggressive when it becomes frightened or nervous, and are known to hiss during these situations. Behavior īoa constrictor occidentalis are nocturnal and are usually independent, not interacting with other members of its subspecies except during mating seasons. Though very rare, it has been reportedly found at elevations above 1,000 m or in areas with rainfall in excess of 900 mm.

The habitat that Boa constrictor occidentalis resides in reaches an altitude of 900–1,000 m above sea level, with rainfall of 250–900 mm. Boas can persist in environments that have been degraded so long as woody plants and scattered trees are present to meet the subspecies' needs. During the day, it will shelter itself within tree hollows, old logs, and, as previously mentioned, animal burrows. Though mostly terrestrial, this subspecies sometimes live in and near trees that they climb for hunting and perching. This subspecies commonly associates with Viscacha ( Lagostomus maximus) burrows, preying on the rodents and using their burrows as refuge. Boa constrictor occidentalis prefers temperatures of 80-85 degrees Fahrenheit with nighttime temperatures of 78 degrees, though they are capable of tolerating temperatures down to 65-70 degrees Fahrenheit. īoa constrictor occidentalis prefers wetlands such as rain forests due to the high humidity and moderate temperatures. Its southernmost limit of distribution in South America rests at 33° 20' S latitude, in the province of San Luis, Argentina. Boa constrictor occidentalis can be found in 13 of the 23 provinces of Argentina and has been estimated to have a historical extent of occurrence that covers approximately 15% of the country's mainland territory, which is about 42.3 million ha. It has the largest distribution of all neotropical boas. Distribution and habitat īoa constrictor occidentalis is an exclusively New World subspecies and is found in Argentina, between the Andes Mountains and the Parana River, Paraguay, and reportedly in Bolivia. Scalation īoa constrictor occidentalis possesses 242-251 ventral scales, 64-87 dorsal scales, 21-22 supralabial scales, and 45 subcaudal scales.

Young members of this species commonly exhibit a pink hue that darkens as they reach sexual maturity. This species usually possesses a grey belly and a dark line running from the neck to the tip of its snout, as well as from the eyes to the neck. Male Argentine boas generally have longer tails in order to contain the hemipenes as well as having longer pelvic spurs that the male uses to grip onto the female and stimulate during copulation.īoa constrictor occidentalis possess a wide range of scale coloration ranging from black specimens with a high rate of contrasting white to specimens exhibiting varying degrees of burnt-orange to red. Female members are much heavier, weighing at an average of 6.13 kg (13.5 lb). Male members of this subspecies on average weigh 4.06 kg (8.95 lb). Whereas adult females can reach lengths of 8 to 10 feet regularly, though some members have been found to reach as long as 4 m (13.13 ft). Adult males reach anywhere between 6 and 8 feet. The Boa constrictor occidentalis subspecies experiences sexual dimorphism, with females being greater in size and weight.

Boa constrictor habitat