Turner Endangered Species Fund Reports Important Success for Long-term Restoration Effort
Bozeman, Mont., — Today the Turner Endangered Species Fund (TESF) announced that the 500th bolson tortoise hatchling recently chipped its way out of the confines of its eggshell on Ted Turner’s Armendaris Ranch in southern New Mexico.
But there was a big surprise: hatchling number 500 was actually two hatchlings! This is not the first set of twins the bolson tortoise project has witnessed, but it is only the second set that has successfully hatched.
The hatchlings are part of a highly successful bolson tortoise breeding and rearing program overseen by TESF to restore the endangered species to the northern Chihuahuan grasslands where it roamed thousands of years ago. Twin hatchlings #500 and #501 are two of over 80 new bolson tortoises that hatched this year from eggs that were deposited by their mothers on the Armendaris ranch earlier this spring. The eggs were collected by TESF biologists Chris Wiese and Scott Hillard, who placed them in an incubator for safe keeping.
A close-up of one of the bolson tortoise twins.
TESF intends to release tortoises #500 and #501, along with many others, to the wild at Turner’s Armendaris and Ladder ranches in New Mexico once they are large enough to survive the trials and tribulations of freedom.
The bolson tortoise (Gopherus flavomarginatus) is the largest, rarest, and least studied of five species of land tortoises native to North America. Weighing a mere 30 g (~1 oz) when it hatches from the egg, a bolson tortoise can weigh up to 14 kilograms (30 pounds) or more as an adult – but it probably takes upwards of 25 years or more for the tortoise to reach that size. Its lifespan is similar to a human’s, living 80 years or more and reaching sexual maturity as a teenager.
Paleontologists believe that about 15,000 years ago, during the late Pleistocene, the species occupied desert grasslands in Mexico, Arizona, New Mexico, and Texas. Today, the only wild population teeters on the edge of extinction in north-central Mexico. The demise of the bolson tortoise was largely caused by humans who hunted and ate them as well as altered – and even destroyed – their ancestral homeland. Bolson tortoises were actually long considered extinct until the small remnant population in Mexico was discovered in 1959. Wild bolson tortoises have been absent from the continental U.S. for over 10,000 years.
Still connected — the twins (hatchlings #500 and #501) are still connected to each other through the nutrition sac that surrounds the egg yolk and sustained them both while in the egg.
A group of 26 adult bolson tortoises housed on the Appleton Research Ranch in southeastern Arizona, where they had been collected and bred since the 1970s, was moved to the Armendaris Ranch in 2006. Two additional breeding pairs were also donated to the Living Desert Zoo and Gardens State Park in Carlsbad, New Mexico where they contribute to the recovery project by producing some of the juvenile tortoises that now live on the Turner Ranches. Together, the 30 adult tortoises comprise the bolson tortoise breeding colony that serves as the main founder population for the restoration project. In addition to the Living Desert Zoo, TESF has partnered with the El Paso Zoo, and renowned tortoise experts to guide the recovery effort.
TESF’s bolson tortoise recovery project aims to establish at least two viable populations in portions of the tortoise’s prehistoric range to promote a secure future for the species while advancing ecosystem integrity.
From a conservation standpoint, having all your tortoise “eggs in one basket” is risky. Hence, establishing new tortoise populations to contribute to the species’ future alongside the existing population in Mexico is a significant contribution to science, society, and nature.
An adult bolson tortoise outside its burrow at Ted Turner’s Armendaris Ranch, New Mexico.
The Turner Endangered Species Fund is a non-profit operational charity dedicated to conserving biological diversity by ensuring the persistence of imperiled species and their habitats with an emphasis on private land. The Fund was established by Ted Turner and his family in June 1997.
The Armendaris and Ladder ranches collectively comprise over 500,000 acres of the most stunning Chihuahuan grassland, desert scrub, riverine mixed forest, and sky island habitat still remaining in the southwestern United States. The ranches are located in the prehistoric range of the bolson tortoise in southern New Mexico and are currently the only restoration sites in the United States for the endangered bolson tortoise.