They're called Gopherus agassizii — Desert tortoise in the vernacular — and are the ancient denizens of western North America.
Today, they are most prominently found in Arizona's Sonoran Desert, as well as in parts of Utah, Nevada and California. But the fantastically fast growth of cities and the explosion of population in the Southwest have served to crowd the desert tortoise out of a great deal of its native habitat.
While all displaced desert tortoises can't be helped, many are being saved through the Arizona-Sonora Desert Museum's tortoise adoption program. Operated under the auspices of the Arizona Game and Fish Department, the program places adult and juvenile desert tortoises with human adoptive families who agree to prepare a proper habitat and maintain the tortoises in as natural a lifestyle as possible.
And, because the life span of a desert tortoise can be 75 years, adoption is a long-term commitment.
"There's this chemistry that people have with tortoises," said Stephane Poulin, ASDM's curator of herpetology, ichthyology and invertebrate zoology. "We don't know what the attraction is, but it's very different than what people feel for dogs and cats. Tortoises are very unusual animals."
Poulin noted that children grow up with images of tortoises and turtles in cartoons, videos and stuffed animals, and seemingly create a bond with such creatures.
The tortoise adoption program typically places 75 tortoises a year with adoptive families. One full-time ASDM staff member and eight volunteers operate the program.
"We don't have a typical adoptive person," Poulin observed. "It's hard to peg who's going to adopt a tortoise — we have people from the elderly to those under age 18, when the parents sign the adoption agreement for them."
The majority of tortoises adopted out to families are juveniles, about six inches long from the front of the shell to the back. The program often has full-grown adults to adopt, but those animals usually are adopted quickly, Poulin noted. Hatchlings aren't adopted out except in very rare cases.
Poulin said if you find an urban tortoise and don't want to keep it, call the ASDM tortoise helpline at (520) 883-3062 and a volunteer will contact you. After some questions, the volunteer will schedule a convenient time to bring the tortoise to the museum to be placed in a new home. ASDM only places animals in apparent good health with custodians.
Depending on the time of year, the finder of the tortoise may be asked to keep it until the museum has space. The adoption program runs from April 2 through Sept. 30. Tortoises usually hibernate during the winter months, generally from November through March.
However, if you find an urban tortoise and want to keep it, the museum's website (www.desertmuseum.org) gives instructions on how to build a tortoise burrow, which plants to have as food in your yard, and how to keep the tortoise healthy.
Poulin noted that before placing a tortoise with a prospective custodian, a program staffer inspects the yard either in person or through digital photos. After any final modifications to the tortoise habitat, the custodian becomes caretaker of the animal.
If you encounter a tortoise in the wild, Poulin suggested keeping a distance from the animal and giving it some space. Avoid handling a wild tortoise because if handled, a nervous tortoise will void its bladder in an attempt to surprise you into releasing it. Desert tortoises have the ability to store water for long periods of time to be used over several months to a year during periods of drought.
"Depending on the time of year, the tortoise might not be able to fill its bladder again and would be unlikely to survive," Poulin said. "So take some photos and memories, but resist touching the tortoise because you also can leave a scent on the animal that might make it easier prey for predators."
The Arizona Sonora Desert Museum tortoise helpline — (520) 883-3062
Facts about tortoises
• It is illegal to collect tortoises from the wild.
• They often hiss and urinate on you if handled.
• They occur on the lower slopes of mountain foothills, in fairly rocky terrain.
• They eat grass, primarily, and occasionally produce such as kale, mustard greens and spinach. Don't feed lettuce, fruit, any meat, or dog and cat food.
• It's best to keep tortoises outside, regardless of their age.
• Tortoises should not be handled by children, and only periodically by adults.
• Male tortoises have an indentation in their plastron (lower shell) near their tail. Females have a flat plastron.
• Males will fight each other even when there are no females present. Females fight sometimes, especially in the fall, just before hibernation.
• Desert tortoises may live up to 80 years or more.
• Prior to the 1950s, many populations reached densities of several hundred tortoises per square mile. Today, most populations contain no more than five to 50 tortoises per square mile.
• Winter hibernation aids in minimizing water loss.
• Social behavior consists of a series of head bobs for species and gender recognition, courtship and threat.
The tortoise was relished as food by the Piman, Paijute and Seri Indians. Shells were used as cooking vessels and as trade items."
Source: The Arizona-Sonora Desert Museum