Volney W. Howard, Jr. Professor of Wildlife Science Department of Fishery and KANGAROO RATS Wildlife Sciences New Mexico State University Las Cruces, New Mexico 88003 Fig. 1. The Ord’s kangaroo rat, Dipodomys ordi Identification and Range Fumigants Damage Prevention and There are 23 species of kangaroo rats Control Methods Aluminum phosphide and gas car- (genus Dipodomys) in North America. tridges are registered for various Fourteen species occur in the lower 48 Exclusion burrowing rodents. states. The Ord’s kangaroo rat (D. ordi, Fig. 1) occurs in 17 US states, Canada, Rat-proof fences may be practical only Trapping and Mexico. Other widespread species for small areas of high-value crops. Live traps. include the Merriam kangaroo rat Cultural Methods Snap traps. (D. merriami), bannertail kangaroo rat (D. spectabilis), desert kangaroo rat Plant less palatable crops along field Other Methods (D. deserti), and Great Basin kangaroo edges and encourage dense stands rat (D. microps). of rangeland grass. Use water to flush kangaroo rats from burrows. Repellents Kangaroo rats are distinctive rodents with small forelegs; long, powerful None are registered. hind legs; long, tufted tails; and a pair Toxicants of external, fur-lined cheek pouches similar to those of pocket gophers. Zinc phosphide. They vary from pale cinnamon buff to a dark gray on the back with pure white underparts and dark markings PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994 Cooperative Extension Division Institute of Agriculture and Natural Resources University of Nebraska - Lincoln United States Department of Agriculture Animal and Plant Health Inspection Service Animal Damage Control B-101 Great Plains Agricultural Council Wildlife Committee their burrows for storage. This caching entrances with soil during the day to activity can cause significant impact on maintain a more constant temperature rangeland and cropland. They remove and relative humidity. They are often seeds from a large area, thus prevent- seen on roads at night, hopping in ing germination of plants, particularly front of headlights in areas where they grasses, in succeeding years. Since occur. these rodents do not hibernate, the Kangaroo rats often occur in aggrega- seed caches are a source of food dur- tions or colonies, but there appears to ing severe winter storms or unusually be little if any social organization hot summer weather. Kangaroo rats among them. Burrows are spaced to are quite sensitive to extremes in tem- allow for adequate food sources within perature and during inclement normal travel distances. Spacing of weather may remain underground for mounds will vary according to abun- several days. dance of food, but well-defined travel Fig. 2. Distribution of Ord’s kangaroo rats in lanes have been observed between North America. General Biology, neighboring mounds. Reproduction, and When kangaroo rats are locally abun- on the face and tail. The largest, the dant, their mounds, burrow openings, giant kangaroo rat (D. ingens), has a Behavior and trails in vegetation and sand are head and body about 6 inches (15 cm) conspicuous features of the terrain. long with a tail about 8 inches (20 cm) Kangaroo rats breed from February to Both the number of burrows and indi- long. The bannertail kangaroo rat is October in southern desert states. The viduals per acre (ha) can vary greatly approximately the same size, but has a breeding period is shorter in the north- depending on locality and time of white-tipped tail. The other common ern states. The gestation period is ap- year. There are usually many more species of kangaroo rats are smaller. proximately 30 days. Reproductive burrow openings than there are rats. The Ord’s kangaroo rat has a head and rates vary according to species, food Each active burrow system, however, body about 4 inches (10 cm) long and a availability, and density of rodent will contain at least one adult rat. tail about 7 inches (18 cm) long. populations. Females have 1 to 3 litters of 1 to 6 young per year. The young There could be as many as 35 rats per are born hairless and blind in a fur- acre (14/ha) in farmlands. In range- Habitat lined nest within the tunnel system. lands, 10 to 12 rats per acre (4 to 5/ha) Usually, the young remain in the nest is more likely. Kangaroo rats do not Kangaroo rats inhabit semiarid and and tunnel for nearly a month before have large home ranges; their radius of arid regions throughout most of the appearing aboveground. activity is commonly 200 to 300 feet (60 western and plains states. The Ord’s to 90 m), rarely exceeding 600 feet (183 Only a few females will breed after a kangaroo rat is the most common and m). They may move nearly a mile (1.6 prolonged drought when food is in widespread of the kangaroo rats (Fig. km) to establish a new home range. short supply. Most females will bear 2). Several other species are located in young when food is abundant, and Mexico, California, and the southwest- some young females born early in the Damage and Damage ern United States. They generally are season will also produce litters before not found in irrigated pastures or Identification the season ends. crops, but may be found adjacent to these areas on native rangelands, espe- All kangaroo rats build tunnels in Historically, kangaroo rats were con- cially on sandy or soft soils. They also sandy or soft soil. The tunnel system is sidered to be of relatively minor eco- invade croplands under minimum till- fairly intricate, and consists of several nomic importance. They have come age in these areas, particularly areas sleeping, living, and food storage into direct conflict with human inter- under dry farming. chambers. The extensive burrowing re- ests, however, with large-scale devel- sults in a fair amount of soil being opment of sandy soil areas for brought up and mounded on the sprinkler-irrigated corn and alfalfa Food Habits ground surface. These mounds can be production. A primary conflict devel- mistaken for prairie dog mounds, par- ops at planting time when kangaroo Kangaroo rats are primarily seed eat- ticularly when observed on aerial rats dig up newly planted seeds and ers, but occasionally they will eat the photographs. They may vary in size clip off new sprouts at their base. vegetative parts of plants. At certain but can be as large as 15 feet (4.5 m) Damage is more severe when popula- times of the year they may eat insects. across and up to 2 feet (60 cm) high. tion densities are high. Smaller popula- They have a strong hoarding habit and tions apparently are able to subsist on will gather large numbers of seeds in Kangaroo rats are completely noctur- waste grain and damage is not as their cheek pouches and take them to nal and often plug their burrow apparent. Since kangaroo rats are B-102 primarily seed eaters, they find irri- excluded by 1/2-inch (1.3-cm) mesh geous because it is thought to present gated fields and pastures a veritable hardware cloth, 30 to 36 inches (75 to little or no hazard of secondary poi- oasis and feed extensively on waste 90 cm) high. The bottom 6 inches (15 soning to small canids and a low haz- grain after harvest. cm) should be turned outward and ard to other nontarget wildlife. buried at least 12 inches (30 cm) in the Kangaroo rats have foiled attempts to Carefully read and follow all label ground. Exclusion may be practical for restore overused rangelands. Their instructions. Zinc phosphide is a small areas of high-value crops, such habit of collecting and caching large Restricted Use Pesticide for retail sale as gardens, but is impractical and too numbers of grass seeds restricts the to and use by certified applicators or expensive for larger acreages. natural reseeding process. In semiarid persons under their direct supervision, rangelands, activities of kangaroo rats Cultural Methods and only for those uses covered by the can prevent an area from making any applicator’s certification. appreciable recovery even though the Alfalfa, corn, sorghum, and other area received complete rest from live- grains are the most likely crops to be Fumigants damaged by kangaroo rats. When pos- stock grazing for 5 years or more. There are no fumigants registered spe- sible, planting should be done in early Reducing livestock grazing is not cifically for kangaroo rats. Aluminum spring before kangaroo rats become enough. As long as kangaroo rats phosphide and gas cartridges are cur- active to prevent loss of seeds. Less remain in an area, they will restrict the rently registered for “burrowing palatable crops should be planted reestablishment of desirable forages, rodents such as woodchucks, prairie along field edges that are near areas particularly native grasses. dogs, gophers, and ground squirrels.” infested with kangaroo rats. Legal Status High kangaroo rat numbers most often Trapping occur on rangelands that have been Live Traps. Trapping with box-type Most kangaroo rats are considered subjected to overuse by livestock. nongame animals and are not pro- (wire cage) traps can be successful in a Kangaroo rats usually are not abun- small area when a small number of tected by state game laws. Certain dant where rangelands have a good local subspecies may be protected by kangaroo rats are causing problems. grass cover, since many of the forbs These traps can be baited successfully regulations regarding threatened and that provide seeds for food are not endangered species. Consult local au- with various grains, oatmeal, oatmeal abundant in dense stands of grass. and peanut butter, and other baits. thorities to determine their legal status Thus, changes in grazing practices before applying controls.