That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

The Desert Tortoise (Gopherus agassizi), was, in the 1960’s, a pet trade staple.  A lack of information as to its proper care and massive habitat loss has today reduced populations to alarmingly low levels.  The species is now protected, and a great deal of research has gone into its husbandry and natural history.  Yet, it seems, few appreciate just how unique this animal is.  Today I’d like to highlight some of its lesser known habits, and how they affect the future of the species.

Tortoise Diversity

Desert Tortoises are one of four tortoise species, all of the same genus, native to North America.  All are terrestrial vegetarians with forelegs modified for burrowing.

An additional 49 species of tortoises inhabit Africa (where they reach their greatest diversity), Europe, South America and Asia.  Tortoises are absent from Australia and Antarctica.

Winter Migrations

Desert Tortoises are found from southeastern California’s Mojave Desert, southwestern Arizona, southern Nevada and southwestern Utah south to northern Baja California and northern Sinaloa, Mexico, and on Tiburon Island in Gulf of California.

It is in the northern part of this range where we find a most unique winter survival strategy. Here, desert tortoises migrate to hilly areas at the onset of cold weather and hibernate in communal burrows that are 15-33 feet in length. It seems that a burrow of suitable length (over 15 feet) could not be dug by a single tortoise in one season, so these long-established burrows (and traditional migration routes) are critical to winter survival.

Effective conservation planning requires an understanding of such factors – permanent hibernation burrows may be far from the tortoises’ summer foraging areas, and thus not recognized as essential habitat when preserves are set aside.  Populations deprived of migration routes to hibernation sites will become extinct in a single winter.

Summer nights are spent in shallow, self dug burrows that are often utilized for many years.

Good Intentions Gone Bad

Another unusual impediment to Desert Tortoise conservation arose when, with good intentions, large numbers of seemingly healthy pet tortoises were returned to the wild.  These animals were responsible for introducing a virulent but difficult-to-detect respiratory illness into wild populations.  Control measures are now in place in the USA.

Desert Tortoises inhabit the centerpiece exhibit of the new reptile house at the Staten Island Zoo, which I was proud to help plan several years ago.  Please see the attached photo above, and visit if you are able.

Further Reading

A wealth of information on Desert Tortoise Conservation is posted here.

A wonderful video of a Desert Tortoise egg hatching is posted here.

The responsive ways of North Africa’s massive Spurred Tortoise are well known to private and professional turtle keepers.  Inquisitive and alert, these arid country natives are quick to become possessive of their territories and, sometimes, owners.  They adjust rapidly to changes in their environments – two 80 pounders that I kept in a half-acre outdoor exhibit at NYC’s Prospect Park Zoo never ceased to amaze me, despite having been under my daily observation for years.

A few years ago, my mother kept an abandoned 30-pound male free-ranging in her yard until a suitable home could be found for him.  He was adopted by a friend, and in short order took over his yard – digging furiously to get at the dog next store, bullying the owner’s dog and ramming or ignoring anyone save his owner.  He never failed to appear when his owner came home, and walked over to sit near him at every opportunity.

In June of this year, a neighbor’s terrier-mix (an annoying, yappy beast, I might add!) got into the tortoise’s yard and, in true terrier fashion, made right for what looked like an easy target.  He managed to bite the tortoise’s front leg – at which point the leg was withdrawn into the shell.  As you may know, Spurred Tortoises have thickly-scaled limbs and immense strength, and use their legs as a shield against predators.  Evolving in a habitat with much larger and fiercer predators that a mere terrier, the tortoise easily pinned the animal between its massive foreleg and shell, and there it remained.

Efforts by several strong men failed to straighten the tortoise’s leg and, in fact, seemed to strengthen his resolve.  Water was poured on the animals, also to no avail.  I was unable to get to the scene, and thought an injection of a muscle-relaxer might be required.  However, I first suggested that the animals, being carefully supported, be submerged in a child’s wading pool.  Thankfully, this did the trick and the tortoise released his wrestler’s “scissor lock”.

Despite having been gnawed on for over an hour, the tortoise’s leg was unmarked.  The terrier, I must say, seemed eager to do battle once again as soon as he cleared the water from his nose – but his owner had more sense!

You can read about the natural history of the African Spurred Tortoise at:

http://nlbif.eti.uva.nl/bis/turtles.php?selected=beschrijving&menuentry=soorten&id=374