1Up Info - A Portal with a Difference

1Up Travel - A Travel Portal with a Difference.    
1Up Info
   

Earth & EnvironmentHistoryLiterature & ArtsHealth & MedicinePeoplePlacesPlants & Animals  • Philosophy & Religion  • Science & TechnologySocial Science & LawSports & Everyday Life Wildlife, Animals, & PlantsCountry Study Encyclopedia A -Z
North America Gazetteer


You are here >1Up Info > Wildlife, Animals, and Plants > Wildlife Species > Mammals > Wildlife Species: Sigmodon hispidus | Hispid Cotton Rat
 

Wildlife, Animals, and Plants

 


Wildlife, Animals, and Plants

 

Wildlife Species

  Amphibians

  Birds

  Mammals

  Reptiles

 

Kuchler

 

Plants

  Bryophyte

  Cactus

  Fern or Fern Ally

  Forb

  Graminoid

  Lichen

  Shrub

  Tree

  Vine


BIOLOGICAL DATA AND HABITAT REQUIREMENTS

WILDLIFE SPECIES: Sigmodon hispidus | Hispid Cotton Rat
TIMING OF MAJOR LIFE HISTORY EVENTS : Diurnal and Annual Activity: Some studies have suggested that hispid cotton rats are mainly nocturnal, but activity has been observed at all hours. Activity patterns appear to be influenced by both biotic and abiotic factors. Hispid cotton rats are active year-round [6]. Breeding Season: Hispid cotton rat populations usually exhibit a bimodal breeding season, with peak litter production occurring in late spring and in late summer-early fall [6]. Rose [67] reported reproductive peaks in March and June for hispid cotton rats; 100 percent of trapped females were pregnant from March through July, but none were breeding in November and December. They do not breed in the coldest winter months. In Kansas breeding is restricted to the frost-free months [6]. Nest Building: A nest is constructed by the female either on the ground surface or in a burrow. Nests are cup- to ball-shaped and woven of grasses [6]. Hispid cotton rats in the northern parts of their range make nests that are thicker and denser, but not larger, than those of southern hispid cotton rats [58]. Gestation and Development of Young: Gestation in hispid cotton rats lasts approximately 27 days. Litter sizes range from 1 to 15 young, with larger litters more typical of northern populations and also of late-season litters. Neonates are well developed; they are mobile and lightly furred but the eyes are not open. The eyes open approximately 18 to 36 hours after birth. Hispid cotton rats are weaned in 10 to 15 days and reach minimum adult size by about 41 days [7,68]. Productivity: Some male hispid cotton rats are sexually mature by 60 days, some females are receptive by 30 to 40 days. The earliest recorded pregnancy was at 38 days [7,68]. Hispid cotton rats have been noted as one of the most prolific mammals in the Southeast. Females bear two to several litters per year depending on latitude and local weather [63]. Females mate within 24 hours of giving birth [6]. Longevity: In Kansas remnant prairie very few hispid cotton rats were recaptured after 8 months [15]. Population Fluctuation: Hispid cotton rat populations are largely sedentary; population density depends mainly on current reproductive effort and not as strongly on immigration [29]. In Kansas remnant prairie hispid cotton rat population density was highest in fall and early winter and lowest in spring and early summer [15]. In the northernmost parts of hispid cotton rat range, severe weather is associated with rapid hispid cotton rat population declines and local extinctions [43]. In Kansas most hispid cotton rat mortality was associated with severe weather in March and April. Populations in the northern part of hispid cotton rat range experience dramatic declines in the nonbreeding season. In many areas local extinction is frequent [52]. In Georgia hispid cotton rat spring abundance in old fields was lowest following drought and extreme winter cold. The reductions in hispid cotton rat populations were associated with sharp declines in vegetative biomass and cover [37]. Effects of Predation: In Georgia a density of 15 hispid cotton rats per acre was considered the predator-limited carrying capacity. Mammalian predators did not have a substantial effect on hispid cotton rat population density. At densities higher than 15 per acre mortality was high; below 15 hispid cotton rats per acre predator-caused mortality was low [55]. Schnell [55] concluded that when diverse and mobile predators are present they are more important than food, social interaction, or weather in limiting hispid cotton rat density. Also in Georgia, 1-acre field enclosures protected from avian predators (covered with a net) were monitored for the effect of avian predators on breeding hispid cotton rat populations. The presence of the cover had no effect on seasonal recruitment or spring-summer mortality; however, autumn-winter mortality was greatly reduced with the cover in place. It was therefore suggested that avian predators are more important than mammalian predators. In addition, it was concluded that nonbreeding (winter) populations suffer substantial losses from predation whereas breeding populations are either able to compensate by replacing lost individuals, are less vulnerable to predation, or both [64]. PREFERRED HABITAT : Hispid cotton rats occupy a wide variety of habitats within their range but are not randomly distributed among microhabitats. They are strongly associated with grassy patches that have some shrub overstory and they have little or no affinity for dicot-dominated patches [26,27]. Habitat use and preference by hispid cotton rats usually appears to depend on the density of monocots. However, some studies are equivocal on the importance of other vegetation [16]. For example, hispid cotton rats may respond favorably to a high percentage of dicots in a stand if cover remains optimal. In Kansas hispid cotton rats increased on root-plowed prairie that experienced an increase in the diversity and biomass of early-successional forbs [19]. Also see discussion of Oklahoma savanna in HABITAT-RELATED FIRE EFFECTS. Male hispid cotton rats exhibit a lower degree of habitat selectivity than females. In Texas males were found on different habitat types (grassy, shrubby, and mixed) approximately in proportion to availability; female hispid cotton rats tended to choose mixed habitats more often than expected based on availability [7]. Habitat use varies with season and breeding status. In Texas grassy areas with some shrubs were preferred in spring and areas with more shrubby cover were preferred in fall [27]. Grassland Habitats: In Kansas remnant prairie the preferred habitat of hispid cotton rats has dense undergrowth and an upper layer of protective vegetation such as big bluestem (Andropogon gerardii)/kochia (Kochia scoparia)/annual sunflower (Helianthus annuus) [15]. Hispid cotton rats prefer grassy clearings, croplands, overgrown fields, and overgrown roadsides and right-of-ways [42]. In Kansas prairies hispid cotton rats occur at relatively high abundance in ungrazed uplands and sandy mixed-grass native prairie, but also prefer disturbed areas. Kaufman and others [24] suggested that the use of disturbed areas was probably important in the recent invasion of hispid cotton rats into north-central Kansas from the northern presettlement limit of their range in Oklahoma. On Texas rangelands hispid cotton rats appeared to respond to increased biomass of standing crop and increases in the proportion of the standing crop in potential food plants such as bristlegrasses (Setaria spp.). Hispid cotton rat density was four times greater on areas planted to exotic grasses including King Range bluestem (Bothriochloa ischaemum) and buffel grass (Enchrus ciliaris) than on native range dominated by windmill grass (Chloris spp.) and Texas wintergrass (Stipa leucotricha) [19]. Succession in Grasslands: In northeastern Kansas hispid cotton rats occurred at high population densities in tallgrass prairie (dominated by perennial grasses); population density declined to levels too low to accurately estimate over 28 years of succession to brush and trees [14]. They are occasionally found in habitats dominated by early successional grassland species (i.e., annual grasses and forbs) [9]. Woodland Habitats: Hispid cotton rats occur in grassy areas or early-successional habitats within open woods. In the Southeast hispid cotton rat population density increases with the density of broomsedge (Andropogon virginicus) and other low growing plants, but declines with succession to brush and trees [29]. In Texas pine-hardwood forests, hispid cotton rats were captured most often in narrow streamside management zones which have more light and thus more ground cover, and slightly less often in wider zones [1]. In central Louisiana longleaf pine-slash pine stands hispid cotton rats were captured in sawtimber, sapling, and regeneration stands but not in pole-sized timber; stands with surface cover were more likely to support hispid cotton rats. Pole-sized timber is dense, little light reaches the ground, and surface cover is minimal [46]. In Louisiana and Mississippi hispid cotton rats were more numerous in cut than in uncut bottomland hardwoods. They were also more numerous in cottonwood (Populus spp.) plantations than in uncut cottonwood stands [65]. In northern Georgia intensive site preparation following clearcutting of pine-hardwood mixtures increases forage production and increased numbers of small mammals (presumably including hispid cotton rats) [11]. Importance of Climate: In Colorado hispid cotton rats occupy semimoist areas with abundant grasses and weeds and appear to be restricted to relatively warm areas [39]. In New Mexico hispid cotton rats do not occur regularly in areas with a mean annual temperature lower than 55 degrees Fahrenheit (13 deg C) and a growing season shorter than 180 days [45]. In Trans-Pecos Texas hispid cotton rats occur at the warmer, low elevations in areas of moderate to dense grassy cover [54]. When water and wastewater are added to baldcypress (Taxodium distichum var. distichum) domes, small mammals including hispid cotton rat move to peripheral areas that are drier. The rising water tables favor marsh rice rats (Oryzomys palustris) over hispid cotton rats [21]. Population Density: Cameron and McClure [68] compiled reports of hispid cotton rat population densities. The mean hispid cotton rat population density range for all studies was 5.3 to 31.1 rats per hectare. Population density ranges in Texas include 1 to 14 rats per hectare in coastal prairie, 17 to 84 rats per hectare in unmowed right-of-ways, 9 to 29 rats per hectare in old fields, 6 to 54 rats per hectare in abandoned fields, and 0.7 to 5 rats per hectare in grass-pricklypear (Opuntia spp.). In Florida population density ranges include 0 to 24 rats per hectare in sand pine scrub, 2 to 47 rats per hectare in pine flatwoods, and 27 to 94 rats per hectare in tropical hammock. In Kansas hispid cotton rat density ranges were 0.2 to 21 rats per hectare in grassland [68]; the highest estimated density was 65.4 hispid cotton rats per hectare in favored habitat [15]. Habitat Patch Size: In a study of the effects of habitat patchiness on movement, hispid cotton rats preferred only the largest patches which were 165 feet by 330 feet (50 x 100 m). Patches were established by mowing strips between blocks of grasses. Hispid cotton rats were present in intermediate numbers on medium sized patches which were 39.6 feet by 79.2 feet (12 x 24 m), but were so scarce on the smallest patches that their movement pattern could not be analyzed [10]. Home Range: In Kansas remnant prairie the average annual home range of adult male hispid cotton rat was estimated as 0.969 acre (0.39 ha) and that of adult females as 0.543 acre (0.21 ha). The greatest distance traveled by an adult male was 330 feet (100 m) and by an adult female was 250.9 feet (76.4 m) [15]. In Texas male hispid cotton rats also had larger home ranges than females. Home ranges were larger in summer and winter than in spring and fall. Home range size was positively correlated with body mass and negatively correlated with population density. There was a relatively high degree of exclusivity (41%), indicating intolerance of conspecifics, particularly of the same sex [7]. In Texas hispid cotton rats found their original home ranges (homed) from displacements of up to 5,000 feet (1,500 m). Returns were relatively high from displacements of up to 990 feet (300 m), suggesting that hispid cotton rats are familiar with the area within that distance. Hispid cotton rats released in areas with no cover homed better than hispid cotton rats released in typical hispid cotton rat habitat [8]. Spencer and others [69] used site fidelity as a measure of an individual's actual home range and concluded that hispid cotton rats have both single-day and multiday site fidelity and therefore establish true home ranges. COVER REQUIREMENTS : On the southern Coastal Plain hispid cotton rats use gopher tortoise (Gopherus polyphemus) burrows for shelter in sandhill scrub dominated by longleaf pine, bluejack oak (Quercus incana) and sand post oak (Q. stellata ssp. margaretta) [35]. FOOD HABITS : Hispid cotton rats are omnivorous, but the major portion of their diet consists of green vegetation. They occasionally consume insects and other small animals [63]. Field observations of hispid cotton rat diet indicate that preferred foods are the stems, foliage, and seeds of crop and wild plants [42]. Golley [18] reported that in the Southeast, perennial legumes and broomsedge comprised a large portion of the diet of hispid cotton rats. They also consumed roots and tubers. In Texas hispid cotton rat diets always included the lower green stems of grasses (which are relatively low in nutritive value); raspberries (Rubus spp.), privet (Ligustrum spp.) fruits, and leaves of fogfruits (Phyla spp.) were consumed as available [50]. PREDATORS : Hispid cotton rats are preyed on by many birds and reptiles, and by other mammals [63]. In Oklahoma hispid cotton rats were a major prey item in the diet of Swainson's hawks (Buteo swainsonii) [3]. In central Missouri hispid cotton rats comprised 19 percent of prey items in red-tailed hawk (B. jamaicensis) nests [62]. Hispid cotton rat remains comprised a substantial portion of short-eared owl (Asio flammeus) pellets in Arkansas [59]. Hispid cotton rats were the third most important prey item of red wolves (Canus rufus) in eastern Texas and Louisiana [56]. In North Carolina bobcats (Lynx rufus) consumed substantial numbers of hispid cotton rats [72]. Hispid cotton rats were a minor item in the diet of Florida panthers (Felis concolor coryi) [40]. In north-central Florida the only direct evidence of predation on hispid cotton rats was the presence of hispid cotton rat remains in a barred owl (Strix varia) pellet. The authors also observed a corn snake (Elaphe guttata guttata) killing a hispid cotton rat just after the rat was released from a trap. The snake apparently had been waiting on the runway where the trap had been set [38]. MANAGEMENT CONSIDERATIONS : The hispid cotton rat is an economic pest in the Southeast where it causes damage to sweet potato, corn, peanut, tomato, sugar cane, squash, carrot, and cotton crops. Hispid cotton rats also take northern bobwhite (Colinus virginianus) eggs and chicks and sometimes reduce northern bobwhite productivity [42,47,63]. In old fields abandoned for 3 years in Georgia, hispid cotton rats consumed up to 2 percent per month of the standing crop of vegetation when at peak population densities. Since hispid cotton rats clip more vegetation than they consume, they also accounted for 10 percent of the monthly litter input. At lower densities hispid cotton rats are relatively unimportant in consumption and litter production [36]. Hispid cotton rats are a reservoir for some human diseases including rabies, Chagas' disease, and Venezuelan equine encephalitis [6]. REFERENCES : NO-ENTRY

Related categories for Wildlife Species: Sigmodon hispidus | Hispid Cotton Rat

Send this page to a friend
Print this Page

Content on this web site is provided for informational purposes only. We accept no responsibility for any loss, injury or inconvenience sustained by any person resulting from information published on this site. We encourage you to verify any critical information with the relevant authorities.

Information Courtesy: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Fire Effects Information System

About Us | Contact Us | Terms of Use | Privacy | Links Directory
Link to 1Up Info | Add 1Up Info Search to your site

1Up Info All Rights reserved. Site best viewed in 800 x 600 resolution.