The Desert Tortoise
On April 2, 1990 the U.S. Fish & Wildlife Service listed the desert tortoise a threatened species. In response Washington County, Utah has undertaken a Habitat Conservation Plan to recover the species.
June 20, 2012
LeRoy W. Hooton, Jr.
Desert Tortoise seen on the Chuckwalla trail in May 2012.
In May, while hiking on the Chuckwalla trail located in the foothills north of St. George, my wife and I encountered four desert tortoises. After years of hiking this area, this was the first sighting we had of these desert denizens. They were scattered over a distance of 100 yards within the trail boundary; each paid no attention to us as they foliaged in solitude on vegetation at the trail's edge.
The trail is part of the 60,000-acre Red Cliffs Desert Reserve, which was established in 1996 as part of an Endangered Species – Habitat Conservation Plan (HCP). The Reserve spans across the north central portion of Washington County in southwest Utah. It is approximately 20 miles wide and 6 miles deep. The Reserve is north of Ivins, Santa Clara, St. George and Washington City, south of Leeds, and west of Hurricane and LaVerkin.
The HCP was developed and managed by Washington County in coordination with the Bureau of Land Management (BLM), U.S. Fish and Wildlife Service (FWS), Utah Department of Natural Resources (DNR), and the State of Utah School and Institutional Trust Lands Administration. The primary goal of the partnership is the recovery of the threatened Mojave Desert tortoise and its habitat. The Reserve's habitat is also important for the propagation of Utah's Gila monsters, sidewinder rattlesnakes, chuckwalla and peregrine falcons who share the area.
The lack of past sightings of the desert tortoise can easily be explained. We learned later that they normally don't frequent the land surface, but rather spend about 95 percent of their lives underground in burrows that can be 3-6 feet deep. This allows them to live in temperatures exceeding 140 degrees Fahrenheit in the heat of summer and the cold of winter. During winter months they go into hibernation. The burrows also help them avoid predators such as Ravens, Gila monsters, Kit foxes, badgers, roadrunners, coyotes and fire ants. Desert tortoise eggs and infants are particularly vulnerable to predators, resulting in a relatively high mortality rate. However, surviving their early years, mature desert tortoises can live to be 80 years old.
It takes one tough reptila to survive in this forbidding desert environment. The desert tortoise's diet consists primarily of wildflowers, grasses and cacti. They get most of their water intake from the plants they eat and during rain events when they drink from temporary rain pools. Physically, their urinary bladders are able to store fluids, which allow them to withstand the desert's aridity. It's reported that an adult can live a year without water intake, relying on its internally stored fluids for sustenance.
The typical height of a desert tortoise is 4-6 inches; its length (shell) 9-15 inches; and weights 8-15 pounds.
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The desert tortoise inhabit the Mojave and Sonoran deserts of southern California, Nevada and Utah. Prior to the 1950s their population flourished with at least 200 adults per square mile; however, since then there has been a 90 percent decline in the population within the Mojave Desert region (including Washington County). Consequently, on April 2, 1990 the U.S. Fish & Wildlife Service listed the desert tortoise as a threatened species. More recent studies have shown the Mojave region population level is 5 - 60 adults per square mile.
In regards to the current desert tortoise population within Washington County, U.S. Fish and Wildlife Service field supervisor Reed Harris notes that the desert tortoise is primarily located in the 60,000-acre reserve. “Their population is monitored every other year,” he said, “and they are holding their own although recent fires have killed or maimed a significant number within the reserve.” Harris further noted that because of the wildfires, DWR and FWS would probably say overall the numbers are down and future increases would be slow because the tortoise population's natality (birth rate) is so low.
Concluding, in response to our sighting of four desert tortoises, Harris said that the Chuckwalla trail area has avoided fires, so the population may be fairly stable there. “They are awesome critters and many locals have lived there all their life and never seen a tortoise in the wild,” he said.
That really makes me feel fortunate, and thrilled to have seen these intriguing creatures – times four.