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Animal Fact Sheets


rosy boa range map


(Lichanura trivirgata gracia)


Classification and Range

Desert rosy boas belong to the family of snakes Boidae, which contains some of the world's largest snakes species: anacondas, reticulated pythons, as well as many smaller forms. The family Boidae is further divided into several subfamilies: Boinae (large boas); Erycinae (sand boas, rosy boas and rubber boas); Pythoninae (pythons) and Calabariinae (burrowing pythons). Snakes of the family Boidae are distributed throughout the tropics and subtropics of both hemispheres, and extend well into temperate western North America. Desert rosy boas range from southern California into northern Baja California, southwest Arizona and adjacent Mexico.


This small ground boa inhabits arid, rocky scrub, brushlands and desert, particularly near streams, spring seeps and canyon floors. Desert rosy boas are found at elevations from sea level to 4,000 feet (1,220 m)..

Length and Weight

Rosy boas reach an average length of 24-42 inches (61-107 cm), and usually weigh 11-21 ounces (300-600 g); females are larger than males.

Life Span

Estimated at 18-22 years.


In the wild: Small mammals and birds At the zoo: Domestic mice


As with most species of pythons and boas, the male's spurs (vestigial pelvic remnants adjacent to the cloaca) play an important role in sexual stimulation of the female. The male slowly and deliberately flicks his tongue rapidly over most of the female's body. If the female is receptive, he gradually assumes a position on top of the female. The male's spurs then come into play, rapidly stroking back and forth on the rear of her body. The female responds by elevating her tail, at which time the male inserts one of his paired copulatory organs, called hemipenes. Breeding season is May-June, and gestation lasts about 130 days. Babies are usually born in October

Life Cycle

Females normally give birth to three to 12 young; babies are independent from birth. The first shed usually occurs within seven to 10 days after birth. During their first year, young usually double in size. Newly born desert rosy boas range in size from 10-12 inches (25-30 cm) at birth. They are mainly active from evening twilight until early morning.

TIght Squeeze

Like other boas and pythons, desert rosy boas can lay virtually motionless and undetected for long periods of time, waiting for prey to pass within striking distance. When in range, the boa strikes out in a single, explosive motion, using its many backward-curved teeth to grab hold of the prey. Quickly wrapping the prey up in the coils of the snakes stout, muscular body, it squeezes until the animal is unable to breathe and succumbs. Prey is then swallowed whole by the snake.

Location at the Zoo

Desert rosy boas can be seen in the Day Exhibit of Woodland Park Zoo's Day and Night Exhibits building. Desert rosy boas are often used for educational "hands on" presentations for zoo visitors.

Conservation Connection

The desert rosy boa comes from the Mojave Desert, where it spends much of its life hiding in rock crevices, hunting for lizards and rodents. The desert rosy boa is very good-natured, and this makes them excellent candidates for pet reptiles. Although the desert rosy boa is strictly protected by California state law, poachers illegally hunt these animals for the pet trade, using crowbars to break open the crevices in which desert rosy boas live. Desert rosy boas, as all reptiles, play an important role in nature's web of life. Wild habitat needed by these reptiles, however, is quickly disappearing. The pet trade is also lowering the numbers of certain reptile populations, to the point where they may become extinct in the wild. Each of us needs to take action to protect wild habitats, so snakes and all animals can continue to perform the vital roles they play in maintaining the delicate balance of nature.

Humans need lizards and other reptiles.

Here are only a few of the benefits they provide:
•Reptiles help keep animal populations in balance.
•Reptiles consume many animals that humans consider as pests, including mice, rats and destructive species of insects. This helps to control disease and damage to crops.
•Snake venom is used in medical research and provides effective medicines to fight certain human diseases.

Reptiles as Pets

We do not recommend reptiles as pets for most people as they require very specialized diets and environments. We also receive hundreds of requests each year to take former pet iguanas, boas and other reptiles but we cannot accept these due to space, health and unknown backgrounds. If you need to find a reptile or amphibian a new home, we suggest you contact a local herpetological group in your area. In the Puget Sound region, contact the Pacific Northwest Herpetological Society as a resource. If you do choose to get a reptile as a pet, please learn as much as possible about their care and the best species before making your decision and never accept wild-caught animals as pets or release non-native reptiles or amphibians into the wild.

How You Can Help!

The effort to save endangered species requires cooperation and support at the regional, national and international levels. You can help in this cause. Join and become active in a conservation organization of your choice. Don't buy products made from wild animal parts. Anyone interested in owning a reptile should learn about its needs and be sure it was captive bred. Many more wild-caught animals die than ever reach pet stores, and those that are fortunate enough to survive are often stressed, malnourished and untamable. Read more about keeping a pet reptile at:

To learn other ways you can help, contact Woodland Park Zoo at about supporting conservation programs at the zoo. Discover more about snakes by contacting the Society for the Study of Amphibians and Reptiles at 303 W. 39th St., PO Box 626, Hays, KS 67601, or the American Federation of Herpetoculture: AFH, P.O. Box 300067, Escondido, CA, 92030-0067. Learn other ways you can help conserve wildlife and habitats by visiting our How You Can Help page.

Sources and Suggested Reading

Burton, Maurice. 1984. Encyclopedia of Reptiles, Amphibians & Other Cold-Blooded Animals. BPC Publishing Ltd., San Sebastian, Spain. 252 p.

Mattison, Chris. 1986. Snakes of the World. Facts On Life Publications, New York, NY. 190 p.

Shaw, Charles E. and Sheldon Campbell. 1974. Snakes of the American West. Alfred A. Knopf, xx, xx. 331 p.

For Kids!

Markle, Sandra. 1995. Outside and Inside Snakes. MacMillian Books, New York, NY. 40 p.

Resmick, Jane P. 1996. Eyes on Nature: Snakes. Kidsbooks, Inc., Chicago, IL. 29 p.

Zoobooks. 1992. Snakes. Wildlife Education, Ltd., San Diego, CA. 16 p.

Desert Rosy Boa Taxonomy

Phylum: Chordata
Species:L. trivirgata gracia

Desert Rosy Boa Fascinating Facts

  • When threatened or disturbed, the Desert rosy boa may coil up into a ball and retract its head into the center of the coils. This provides its enemy the smallest possible body and protects the head from attack!