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Please note: On Wednesday April 24 at Franklin Park Zoo and Thursday, April 25 at Stone Zoo, volunteers, zoo employees and local emergency responders will take part in routine animal escape exercises. While the exercise is occurring, guests have the opportunity to participate in the evacuation portion, and may be asked to move to certain areas within the Zoo for a brief period of time (not to exceed 10 minutes). These exercises are an important part of our preparedness training, and we appreciate your participation and understanding. If you have any questions about what to expect, please don't hesitate to contact us at 617-989-2000 or info@zoonewengland.org.

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Rosy Boa

Lichanura trivirgata

Rosyboa Gallery

About the Rosy Boa

conservation status: least concern

Geographic Range:

range map

Class: Reptilia  
Order: Squamata  
Family: Boidae  
Genus: Lichanura  
Species: trivirgata 

Among the smallest members of the boa family, the rosy boa prefers the rocky terrain of the southwestern United States and northwestern Mexico. The rosy boa compensates for its vulnerable size with a clever way of warding off predators—rolling itself into a ball with its head in the center, and then releasing a foul-smelling musk from a gland in its tail. This habit of coiling around its own head appears to make it difficult for predators, like birds of prey, to kill or even handle a rosy boa.

Rosy Boa Facts

Appearance:

The rosy boa is one of the smallest members of the boa family. It has a heavy-bodied build, a short, blunt tail and small head. Its eyes have elliptical pupils like those of a cat. They are beige, blue or rose colored with three lengthwise gray, tan or reddish brown stripes, and the underside is creamy or gray with black flecks. Individuals from the coast and foothills may be nearly a uniform gray or brown color, with less defined stripes. Individuals from the desert tend to exhibit a more distinct pattern of stripes. Like other members of the boa family, the rosy boa has two claw-like spurs near its vent, attached to bones inside its body. These anal spurs are vestigial hind legs inherited from the boa's lizard ancestors.

Size:

Length: 22.4–35.4 inches

Diet:

Rosy boas feed on warm-blooded prey, such as small mammals and birds. Like its larger relatives, they kill prey by constriction.

Reproduction:

Rosy boa breeding season takes place in the spring, after which soft eggs are retained and developed inside the female for a gestation period of four months. Females give live birth to up to 12 offspring.

Behavior:

These snakes are usually most active at dusk and at night, and they're diurnal in early spring. In early spring, or in cooler coastal areas, they may be active during the day. Rosy boas are primarily terrestrial but will also climb low shrubs. They spend much of their time hiding under rocks.

The rosy boa compensates for its vulnerable size with a clever way of warding off predators—rolling itself into a ball with its head in the center, and then releasing a foul-smelling musk from a gland in its tail. This habit of coiling around its own head appears to make it difficult for predators, like birds of prey, to kill or even handle a rosy boa.

Habitat/Range:

The rosy boa inhabits desert foothills with rocks and boulders from sea level to 4500 feet. This snake prefers rocky terrain where crevices make safe homes. Occasionally, it is spotted in shrub lands or chaparral without rocky areas. The rosy boa is restricted to southern California, southwestern Arizona, and northwestern Mexico.

Median Life Expectancy:

10-15 years