Turtles and tortoises come in all shapes and sizes. They range in size from the 4-inch Bog Turtle to the 1500-pound Leathery Turtle. Various species of turtles can be found around the world on every continent except Antarctica.
Turtles have been on the earth for more than 200 million years! They evolved before mammals, birds, snakes, and lizards. Many zoologists believe that turtles survived so long because of their unique shells. The upper shell is called a carapace and the lower shell a plastron.
Despite their protective shell, they are vulnerable and need our protection. Over collection, habitat destruction and fragmentation, disease and climate change are serious threats to turtle survival. This World Turtle Day, and every day be kind to turtles.
The Sonoran Desert National Monument is home to two species of turtle, the Sonoran Desert Tortoise Gopherus morafkai and the Arizona Mud Turtle Kinosternon arizonense.
Sonoran desert tortoises are masters of their environment. They survive the hot dry summers by spending most of their lives in burrows where temperature and humidity are amenable to them. They surface when conditions are favorable to eat and breed. Their most active time is in the spring where they forage and build up fat reserves and water which is stored in their bladder. Most of their water comes from the plants they eat.
Height: 4-6 inches
Length: 9 – 15 inches
Weight: 8 – 15 lbs.
Lifespan: 50 – 80+ years; Females do not breed until they are 15 – 20 years old.
Diet: grasses, forbs (Non-grass annuals i.e. wildflowers), some shrubs, new cactus growth and flowers
Mating Season: Late summer to early fall
Gestation: 10 – 12 months
Clutch size: 4 -6 eggs
Rocky foothills, desert washes throughout the Sonoran Desert National Monument where suitable burrows are available or easily constructed. Desert tortoises may use the same burrow for many years.
Collecting or harassing wild desert tortoises is illegal in Arizona. If you encounter a desert tortoise in the wild please do not handle it. Desert tortoises may release the contents of their bladders as a defense mechanism against predators. A tortoise with an empty bladder may succumb to dehydration.
Important Note: The FSDNM has been conducting tortoise surveys for the last two months. No tortoises have been observed in the northern part of the SDNM. It is very dry and there is very little forage available. The tortoises in this area will undoubtedly remain in their burrows until conditions improve.
Special thanks to George Andrejko of the Arizona Game & Fish Department for providing the desert tortoise image above.
The Arizona mud turtle is perhaps the rarest inhabitant of the Sonoran Desert Nation Monument. Like the desert tortoise they have adapted to conditions that make them a remarkable animal.
The Arizona mud turtle has a yellowish-brown carapace and a yellow plastron. It reaches about 6 inches in length. The neck and throat are yellow or cream, and the neck has small tubercles for sensing prey in their sometimes muddy habitat.
The Arizona mud turtle is limited in Arizona to the south-central part of the state, mostly on the Tohono O’odham Nation. Only one specimen has been identified in the SDNM. It is also found in north central Mexico.
This species is usually encountered in rain filled temporary bodies of water, such as charcos or stock tanks, pools, or roadside ditches within various p Sonoran desert communities.
Mating occurs in the summer and eggs are laid in underground nests. Incubation is about 11 months. Young turtles will hatch when the monsoon returns.
Special thanks to Randy Babb for providing the image of the Arizona Mud Turtle and to Tom Brennan for providing the natural history information on this special turtle.