DFG News Archive

More Desert Tortoises Falling Prey to Pet Lovers Dwindling Population Numbers Attributed to Illegal Collection, Off-road Vehicles

Looking to curb the declining population of the threatened desert tortoise, the Department of Fish and Game (DFG) reminds anyone who enjoys California’s eastern desert regions that it is illegal to remove the slow-moving reptiles from their natural habitat.

Additionally, DFG cautions pet owners who grow weary of their domestic tortoises not to release the reptiles in the southern California desert. Released tortoises have a low survival rate and can spread disease within the dwindling tortoise population.

“This is tortoise-activity season, the time of year when they’ve emerged from their burrows and can find good vegetation and water,” said Rebecca Jones, an environmental scientist with DFG’s Eastern Sierra-Inland Desert Region. “This is also the season, usually late May to July, when they lay eggs.”

Jones warned that one of the growing problems for the shrinking numbers of desert tortoises is that people find the dome-shelled reptile and decide to take them home.

“People collect them from the desert, thinking that they’d make good pets,” Jones said. “These animals are protected under the California and the federal Endangered Species Act, and yet we get up to 40 calls a year from people who say they’ve found one and asking what should they do with it.”

California’s desert tortoise population appears to be in rapid decline throughout the west Mojave, east Mojave and Colorado deserts. The tortoise, which can weigh up to 15 pounds and reach 15 inches in length, survives in parts of southwest Utah, Nevada, Arizona and northern Mexico. Research shows that even populations that were thought to be stable or increasing a decade ago are now also in decline.

This month, DFG is distributing up to 2,500 posters to make people aware of the plight of the desert tortoise. In addition to regional offices, DFG hopes to place the posters at schools, rest areas, grocery stores and gas stations.

“The posters are designed to inform the public that these animals are protected by law and it is illegal to collect them,” Jones said. “The problems that afflict the desert tortoise aren’t just from the people who live in California’s desert region. It potentially comes from anyone who comes to the region and does something that disrupts the balance.”

Scientists have studied the population and habitats of desert tortoises (Gopherus agassizii) for decades, using carefully placed study plots in the heart of tortoise habitat. Beginning in the 1970s, scientists established 27 study plots to help monitor the state’s population.

Jones said the plots are invaluable because they give environmental scientists data sets to analyze demographic attributes of tortoises, health and disease in tortoises, changes in vegetation and anthropogenic impacts. Since monitoring began, there has been a decrease in some populations of nearly 90 percent. Some areas that once had healthy populations of 250 tortoises per square mile now have fewer than 10 per square mile, Jones said.

It is against the law to remove a desert tortoise - or any listed species - from its habitat, under the California Fish and Game Code.

While the illegal take of tortoises remains a concern, scientists attribute elevated mortality rates to numerous causes including: vandalism, upper respiratory tract disease, off-road vehicles that either crush them or destroy their habitat, trampling by livestock and predation by common ravens and feral dogs.