Zokors are burrowing rodents found across parts of China, Kazakhstan, and Siberian Russia, resembling mole-rats in appearance. Highly specialized for living underground, they spend most of their lives there. Their presence is often indicated by mounds of soil created during their digging activities, as they are rarely seen above the surface.
Physical Characteristics and Adaptations
Zokors possess a compact, cylindrical body, ranging from 15 to 27 centimeters (about 6 to 10 inches) in length, excluding their short tail. Their dense, soft fur varies from grayish to reddish-brown, providing camouflage in their underground environment. Their powerful front claws are specifically adapted for excavating soil. The third claw on each forefoot is particularly strong, with the longest claws being at least three times the length of those on their hind feet.
Zokors have small eyes that often appear almost invisible, hidden beneath their fur. This adaptation reflects their life in low-light conditions underground. They also lack external ears, with only small openings present, which helps prevent soil from entering while they burrow. Their strong, chisel-like incisors protrude slightly from their mouths, serving as tools for gnawing through roots and soil during excavation.
Underground Life and Behavior
Zokors are expert burrowers, constructing intricate tunnel systems that serve various purposes. These subterranean networks include a nesting chamber for resting, a food storage chamber, and a “toilet” chamber for waste. The main burrow is located about 2 meters (6.6 feet) below the surface, with several shallower foraging tunnels radiating outwards, some extending up to 100 meters in length.
When digging, zokors use their front feet to loosen and push soil underneath their bodies, then kick the excavated dirt backward with their hind legs, creating characteristic mounds on the surface. Zokors are solitary and territorial, defending their burrow systems from intruders. Their diet consists of underground plant parts, such as roots, bulbs, rhizomes, and tubers, which they collect and store in their burrows, particularly for colder seasons. While active throughout the year, their activity levels peak during spring and autumn.
Ecological Significance
Zokors play a significant role in their ecosystems, often described as “ecosystem engineers.” Their constant burrowing activities directly impact soil health and structure. By creating tunnels and moving soil, zokors aerate the ground, improving air circulation and water penetration. This aeration allows water to reach plant roots more easily, benefiting overall plant growth.
The mounds of soil brought to the surface also contribute to a heterogeneous distribution of nutrients, which can increase plant diversity. Their burrowing also helps prevent soil erosion by increasing the soil’s capacity to retain water. For example, the Chinese zokor (Eospalax fontanierii) positively influences alpine meadow ecosystems on the Tibetan Plateau through its bioturbation activities. Beyond their direct impact on soil and vegetation, zokors also influence other animal species. Their burrows provide refuge and breeding sites for various animals, and they serve as a food source for numerous predators, including Chinese mountain cats and eagles.
Classification and Diversity
Zokors belong to the subfamily Myospalacinae, part of the family Spalacidae, which also includes blind mole-rats, African mole-rats, and bamboo rats. There are six recognized species of zokors, divided into two genera: Myospalax and Eospalax.
Myospalax Genus
False zokor (M. aspalax)
Siberian zokor (M. myospalax)
Transbaikal zokor (M. psilurus)
Eospalax Genus
Chinese zokor (E. fontanierii)
Rothschild’s zokor (E. rothschildi)
Smith’s zokor (E. smithii)
Historically, zokors were thought to be more closely related to hamsters or voles. However, recent molecular phylogenetic studies show they are more closely related to blind mole-rats, root rats, and bamboo rats within the family Spalacidae. This evolutionary relationship suggests one of the earliest significant splits within muroid rodents occurred between burrowing and non-burrowing forms. The divergence between the Myospalax and Eospalax genera is estimated to have occurred approximately 8.8 million years ago.