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THE BAJA POST
NEWSROOM
SOURCE: PR NEWSMEDIA
Seventy critically endangered Mojave desert tortoises have successfully emerged from their winter burrows after being reintroduced into their native habitat on Edwards Air Force Base in Southern California.
San Diego Zoo Wildlife Alliance and The Living Desert Zoo and Gardens, the global authority on desert plant and wildlife conservation, are working in partnership with Edwards Air Force Base, the U.S. Fish and Wildlife Service and the U.S. Geological Survey, using headstarting techniques designed to increase the survival rate for young tortoises.
The cohort of young tortoises was the first in the program to be reintroduced into the wild after receiving a combination of an indoor- and outdoor-rearing. Within 24 hours of reentering their native habitat, the tortoises were exhibiting positive natural behaviors by constructing new burrows or modifying existing burrows for shelter.
Now, six months later, they have emerged after winter brumation—a state of deep sleep specific to reptiles—and are spending more time basking at burrow entrances. Scientists are currently conducting health assessments and replacing radio transmitters on the tortoises to continue monitoring their success and better understand the juvenile age class.
Scientists track gravid (egg-carrying) desert tortoises, monitor the adult females as they lay eggs in human care and rear the hatchlings for one to two years. The hatchlings are reared indoors at The Living Desert for six months, and then in a protected outdoor environment at Edwards Air Force Base.
By reintroducing the tortoises into native habitat when they are no longer at their most vulnerable, conservationists are giving juvenile tortoises a fighting chance at survival—as evidenced by the success of the first reintroduced cohort. Indoor rearing at The Living Desert enables the tortoises to grow to three to five times the size they would at this stage in their native habitat, making them less vulnerable to predation.
This keystone species in the Southwest United States serves as a prime example of the dangers of a changing climate. In September 2023, the nests of a second headstart cohort—laid in protected outdoor habitats at Edwards Air Force Base—were once again excavated under emergency circumstances. Predatory ants and fly larvae attacked hatchling tortoises as they emerged from their shells. It is believed the historic arrival of Hurricane Hilary created extra moist conditions, leading to a breeding ground for these insects.
The surviving tortoises received veterinary care at The Living Desert. The cohort—following in the footsteps of their predecessors—was reared indoors at The Living Desert for the first six months of their life. This month, they will be transferred to the outdoor headstart habitats at Edwards Air Force Base managed by San Diego Zoo Wildlife Alliance, where they will spend the next six months. At approximately one year of age, they will be reintroduced into their native habitat.
