The Mojave desert tortoise is found in the United States’ Mojave Desert, as well as in other dry habitats in the southwestern United States. This rare reptile is seldom seen due to its burrowing lifestyle and the fact that it hibernates for up to nine months of the year.
As a result of habitat loss this desert reptile is becoming scarce. Its conservation status has been Vulnerable since the ‘80’s.
Mojave Desert Tortoise Facts At A Glance
- Other Name(s): Mohave desert tortoise, Agassiz’s desert tortoise, California desert tortoise
- Scientific name: Gopherus agassizii
- Type of Animal: Reptile
- Animal Family: Testudinidae (the tortoise family)
- Where Found: Southwestern United States
- Habitat: Desert, Arid Regions
- Length: 15 to 36 cm (5.9 to 14.2 in)
- Weight: 11 to 23 kg (24 to 51 lb.)
- Conservation Status: Vulnerable
- Other interesting Mojave desert tortoise facts: The bladder of the Mojave Desert tortoise can store up to 40% of its weight in water.
Meet The Mojave Desert Tortoise
The Mojave desert tortoise is a slow-moving reptile found in deserts and other dry regions in the southwestern United States. The species is the largest terrestrial (land) turtle in the United States.
You can see footage of the desert tortoise in the video below:
The Mojave desert tortoise (Gopherus agassizii) and the Sonoran desert tortoise (Gopherus morafkal) were previously thought to be the same species. Due to differences in their DNA and behavior (as well as the areas in which they are found), the two are now classified as separate species.
What Does The Mojave Desert Tortoise Look Like?
The Mojave Desert tortoise has a domed carapace (top shell) made up of large scutes. (A scute is a hard plate made of keratin, the same natural substance out of which our own fingernails are made.)
At the front of the plastron (the tortoise’s under shell) there is an extension called the ‘gular horn’. The male desert tortoise’s gular horn is longer than that of the female.
The tortoise has sturdy, shovel-like front limbs, which are equipped with long nails for digging. Its back legs are skinnier and longer.
The desert tortoise’s carapace ranges from tan to dark brown in color. The center of the shell is sometimes lighter, and usually lacks any pattern. The plastron, limbs and neck are brownish or yellowish in color.
Males are generally larger than the females and also have longer tails. The male’s shell is also shaped differently: as well as having a longer gular horn, the plastron is depressed rather than flat.
Mojave Desert Tortoise Facts: Range
The Mojave Desert tortoise is found in the southwestern United States. Its range extends from southeastern California to western Arizona and extreme southern Nevada and southwestern Utah. The species occurs throughout the Mojave Desert.
Mojave Desert Tortoise Habitat
The Mojave Desert tortoise lives in a variety of arid habitats, including sandy dunes, riverbanks, canyon bottoms, desert oases and rocky hillsides. The animal is able to tolerate areas with high temperatures but requires firm ground to be able to dig burrows.
The species can be found from sea level to elevations of up to about 1,600 m (5,300 ft.).
If you were hoping to see a desert tortoise next time you visit the Mojave Desert, then you may be disappointed. They species spends most of its time underground, and hibernates for up to nine months of the year.
Even where desert tortoises are most abundant, there may only be one found in every 2.5 acres. Most areas are even more sparsely-populated.
The Mojave Desert tortoise spends up to 98% of its life in burrows and rock shelters. Staying underground helps it survive cold temperatures in winter and also prevents water loss during the hottest part of the summer.
The species hibernates between October and April. Its activity peaks in spring, when the tortoise comes out during the daylight hours to feed and mate. During active periods, it may travel up to 200 m (660 ft.) in a day.
The Mojave Desert tortoise is known to dig multiple burrows. Those used in the summer are shorter and shallower than those used in the winter.
The largest burrows can be up to 10 m (33 ft.) long and 1m (3 ft.) deep. The tortoise may occasionally share a burrow with one or more desert tortoises and even with other species.
In general, the Mojave desert tortoise is not highly social.
The Mojave Desert tortoise communicates using a variety of sounds (including hisses and grunts) and postures. Both droppings and secretions from anal glands may also be used to mark a burrow or a home range.
Desert Tortoise Life-Cycle
Mating takes place between March and April, shortly after the tortoises emerge from hibernation.
Males fight one another for mating rights with a female. This involves posturing, bobbing of the head, and the use of gular horns to ram and even flip over an opponent.
Courtship itself is also aggressive, with the male biting and butting the female before mating takes place.
Between May and July, the female digs a hole and lays a clutch of 4 to 12 ping-pong ball-sized eggs. These are round, off-white and hard-shelled. She urinates throughout the process (possibly to deter predators or to provide moisture) and will often linger near the eggs for some time to guard them.
The incubation period is dependent on temperature, and lasts for between 90 and 135 days. The eggs hatch between August and October. The hatchlings have very soft shells, which only begin to harden when the tortoises reach around 5 years of age.
What Do Mojave Desert Tortoises Eat?
The Mojave Desert tortoise is herbivorous (plant-eating). It mainly feeds on grasses, but other plant material, such as herbs, flowers and succulents (fleshy, water-retaining plants such as cacti), are also consumed.
The tortoise also ingests soil and small rocks. This is possibly for additional calcium and other minerals, and also to help with digestion.
Feeding mainly takes place in the spring over a period of 6 to 12 weeks. The tortoise is toothless; instead of chewing it grinds food with its beak.
The Mojave desert tortoise gets most of the water it needs from its food. An adult can survive for over a year without drinking, relying instead on the water stored in its large bladder and by conserving water by staying underground.
Mojave Desert Tortoise Predators
Mojave Desert tortoise eggs, hatchlings and juveniles are highly vulnerable to predation. Predators include common ravens, feral dogs, gray foxes, Gila monsters, badgers, roadrunners, golden eagles and fire ants.
Adults are protected by their hard shells, but may fall prey to animals such as cougars, coyotes and kit foxes.
Is The Mojave Desert Tortoise Endangered?
The Mojave Desert tortoise is rated ‘Vulnerable’ by the International Union for Conservation of Nature (IUCN).
The species has declined by as much as 90% in some areas since the 1980s, and the Mojave Desert population is listed as threatened in the USA.
The species faces many threats, including:
- Habitat loss and fragmentation: Increased human activity has caused the loss and fragmentation of desert tortoise habitat. These activities include: urban, military and agricultural development, mining, and the use of off-road vehicles.
- Other species: Both the spread of invasive plant species and overgrazing by domestic livestock have had a negative effect on desert tortoise habitat. An increase in the number of ravens and wild dogs also increases predation pressure on young tortoises.
- Disease: A disease known as upper respiratory tract disease (URTD) has caused a decline in the Mojave desert tortoise population.
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