Kangaroo Rats Pocket Mice and Kangaroo Mice: Heteromyidae

Heteromyids are nocturnal, active at night, rodents. Kangaroo rats and mice move about mostly by hopping on their hind limbs, while pocket mice use all four of their limbs in a walking motion. They have a very basic social structure, mostly living alone except for females and young. They do interact with nearby neighbors, which are often relatives. Most species burrow tunnel systems with multiple chambers and surface openings.

Heteromyids have well-developed communication systems. Medium- and large-sized kangaroo rats communicate by drumming or thumping the ground with their large hind feet; familiar thumping identifies neighbors, while strangers are not recognized. Each species has its own set of drumming patterns, which are heard through the air and ground.

Male home territories overlap with those of other males and females. Females occupy a territory that contains no other females. They regularly bathe in sand, which helps to clean their hair and to deposit their scents onto the ground. Their scent informs other heteromyids and other animals about their sex, identity and mating status. When a predator, an animal that hunts other animals, is seen, heteromyids use their body coloring to hide and avoid them. If needed, they will run away along a crooked path. Desert heteromyids also have strong hearing that lets them hear approaching predators.

Males always travel to female territories during breeding season in order to mate. Mating relationships range from one male and one female, to several males competing for access to one breeding female. Larger and medium sized kangaroo rats drum their feet in order to chase away competing males. Females prefer to mate with males they know, but will mate with strangers if necessary. Males will mate with any females. Breeding occurs only when enough moisture is available for nursing females to provide milk to young. Females produce several litters, group of young animals born at same time from the same mother, each year, but the number depends on environmental conditions. Litter sizes range from one to nine, but average three to four in most species. They live ten years or longer.