The Chihuahuan Desert of northern Mexico is the home to the largest terrestrial reptile in North America, the Bolson Tortoise. Its shell can be up to 40 cm (approx. 16”) long, which is small in comparison to its ancient ancestors that were double that size. 

Bolson Tortoises are real engineers. Due to the challenging climatic conditions in the desert, they like to dig long tunnels to hide out from the heat and also to avoid encounters with predators. Those tunnels can be as long as 8 meters. Adult tortoises spend 99% of their lives underground and only like to come to the surface during rain, which is one reason why we don’t get to see them very often. 

Sadly, another reason for their absence is the decline in numbers. Originally, the Bolson Tortoise was also found in the deserts and shrublands of Arizona, New Mexico and Texas. But people in the past and even today use them as food and destroy their environment through agriculture, which has put the reptile into the category of “critically endangered” species. 

Nevertheless, there is hope for our slow-moving friends. In 2016, the Bolson Tortoise Ecosystem Preserve was established in Mexico, which protects the tortoise and the desert ecosystem it lives in (Turtle Conservancy). Furthermore, people of the Turner Endangered Species Fund have started to raise Bolson Tortoises in New Mexico and hope to release them back into the wild deserts of New Mexico and Texas (TESP). Hopefully, we will come across their underground engineering projects soon again also in the United States. 

Write up by Charlotte Walter

IUCN Red List, https://www.iucnredlist.org/species/9402/112660985. 
Turtle Conservancy, https://www.turtleconservancy.org/programs/bolson-tortoise. 
Turner Endangered Species Fund (TESP), http://tesf.org/project/bolson-tortoise/.