Testudo horsfieldii is a rugged little tortoise which is included in the genus Testudo, but is currently assigned to its own sub-genus Agrionemys. It is known by at least six common names, including the Russian, the Afghan, the steppe, the central Asian, the four-toed and Horsfield's tortoise, resulting in some confusion when seeking information about it. For the sake of brevity, the Russian/Afghan/steppe/central Asian/four-toed/Horsfield's tortoise will be referred to hereafter as the Russian tortoise.
The Russian tortoise is the easternmost of the five tortoises collectively known as Mediterranean tortoises. They are "so-called" because their native ranges occur in proximity to the Mediterranean Sea which lies south of Europe and north of Africa. The other Mediterranean tortoises are Testudo graeca (spur-thighed tortoise), T. hermanni (Hermann's tortoise), T. marginata (marginated tortoise) and T. kleinmanni (Egyptian tortoise).
The range of the Russian tortoise extends from southeastern Russia southward through eastern Iran, northwest Pakistan and Afghanistan. It inhabits dry, barren localities such as rocky deserts and hillsides and sandy or loamy steppes, often at elevations of 5,000 feet (1,500 m) or higher. In these arid regions, the tortoise is frequently found near springs and brooks where grasses and other vegetation are relatively abundant.
The Russian tortoise has a rounded-oval carapace, and is 6-8 inches (15-20 cm) in length, although individuals in excess of 9 inches (23 cm) are occasionally reported. The carapace is distinctly flattened along the vertebral scutes. Coloration of the carapace varies, from a light tan through yellow-green to olive, often with brown or black markings on the larger scutes. The plastron is usually blotched with brown or black on each scute, and in some cases is solid black. The plastral hinge between the abdominal and femoral scutes which occurs in some other Mediterranean tortoises, is absent. The rear marginal scutes, on either side of the tail, are enlarged and often slightly serrated, more so in the male than in the female. The tip of the tail is hard and bony. The tail of the male is significantly larger than that of the female. The skin of the tortoise is usually yellowish-tan. This tortoise is the only Testudo with four claws on each foot, resulting in one of its common names, the four-toed tortoise.
In habitat, the Russian tortoise is primarily a burrow-dweller. It prefers sandy or loamy ground in which to dig its burrow. The burrow is usually 30-78" (80-200 cm) long, ending in a widened chamber in which the tortoise is able to turn around. Spring rains are necessary to soften the soil sufficiently for the tortoise to dig its burrow. As the ground dries out, the soil hardens into a solid crust, making excavations virtually impossible. The Russian tortoise retires to its burrow during the midday heat, as well as at night during its active period. In favored locations, many burrow exist in close proximity. Tortoises are known to visit adjacent burrows, and sometimes several tortoises spend the night in a single burrow.
The Russian tortoise in the wild has a rather short period of peak activity, only three months out of the year. The tortoises emerge from hibernation in early spring (March-May) and immediately begin seeking mates. Their courtship and mating ritual is somewhat unusual. The male approaches and repeatedly circles the female, then stops to face her head-on. He extends his neck and stares directly into her face while rapidly jerking his head up and down. This ritual may include occasional biting and ramming of the female by the male. Copulation is accompanied by a series of high-pitched "clucking" or "squeaking" sounds.
In May or June, the female lays 2-6 eggs, and may lay two (possibly three) additional clutches during the same season. The eggs usually incubate for 80 to 110 days in the wild. Hatchlings emerge in August or September, but sometimes the hatchlings overwinter in the nest and do not emerge until the following spring. In an incubator in captivity, where eggs are kept at a relatively constant temperature of 87° F (30.5° C), an incubation period of 60 to 75 days is typical. Hatchlings normally measure 1.25-1.33 inches (32-34 mm) in length. Growth is slow in this tortoise. While they reach sexual maturity at 10 years, they are considered full-grown at 20 to 30 years of age.
The Russian tortoise remains active until June or July when activity slows. Summer temperatures exceeding 85° F (29° C) can be problematic; so, the tortoise generally emerges from its burrow only at dawn or at dusk in order to forage when temperatures are lower. Their ephemeral food plants are gone by this time as well. Many tortoises spend the summer in estivation, emerging briefly at the end of summer to feed on dried grasses and twigs prior to hibernation.
Winters in their arid highland habitat can be very harsh and cold. The temperature in much of the tortoise's range is well below freezing. Scientists speculate that the body fluids of the Russian tortoise contain a substance like antifreeze to help it survive frigid temperatures. Records indicate that it is able to withstand a body temperature as low as 3.3° F (-4.8° C). However, Pursall in "Mediterranean Tortoises" indicates that body temperatures lower than 36° F (2° C) may cause irreversible physical damage, and possibly death, due to the freezing of fluids in sensitive organs. The depth of its burrow (up to 6.5 feet/2 m) also helps insulate the tortoise from the ravages of winter.