Reproduction

Egg-laying occurs from May to June. Each clutch will include between 2 and 15 eggs with as many as 3 clutches laid each year.

During the breeding season males will regularly fight one another. Small horns are present on the chest they can use to knock one another over. The loser is flipped on to its back. They can eventually wiggle themselves back on to their front.

Females may not lay their eggs immediately after mating. Instead they can store sperm and wait for optimal conditions to lay the golf ball sized eggs.

These clutches are incubated for between 90 and 135 days.

At hatching the young are fully independent and will set out to find food. A juvenile desert tortoise will measure between 4.2 and 4.5cm (1.6-1.7in) long.

Sexual maturity is reached between 15 and 20 years old. Less eggs are laid in years with little to no rainfall.

Behavior

As an ectotherm the desert tortoise must regulate its own body temperature and aim to reduce water loss. To achieve this they spend much of their time hiding in a burrow or rock shelter. As much as 95% of their life may be spent in the burrow.

During warm weather they will burrow alone. In winter groups burrow together to share body warmth.

Throughout winter they enter a period of brumation where they are inactive for much of this part of the year. In spring they will emerge and begin to bask in the sun to warm their body.

A range of vocalizations are made by the desert tortoise. These include a hiss, grunt and moan. They also use visual communication such as head bobs.

Predators and Threats

Natural predators of the desert tortoise include birds of prey such as ravens, kit foxes and coyotes. Juveniles face additional predators including badgers, skunks, roadrunners and lizards such as the gila monster.

Over the last 20 years the desert tortoise population has declined by around 90%.

One threatening factor has been the use of off-road vehicles. These will destroy plants which the tortoises rely on for food. Some of these habitats can take up to 200 years to recover.

These vehicles may also run over burrows and bury the tortoise alive.

They may be outcompeted for food by domestic animals such as cattle.

Humans have increasingly developed their habitat or destroyed it during building projects.

Desert tortoises were given federal protection in the United States during 1989.

Quick facts

These animals are also known as the gopher tortoise as they live underground like gophers do.

They are referred to as the mojave desert tortoise.

The desert tortoise is recognized as the state reptile of California.