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Peromyscus Genetic Stock Center


Peromyscus leucopus White-footed mouse

*Information adapted from Mammalian Species, No. 247, pp. 1-l0, 1985.

GENERAL STATEMENT

P. leucopus is a grayish or brownish rodent and is found over a large geographical area covering much of the eastern two-thirds of the United States and parts of southern Canada and northern Mexico. Also known as the wood mouse, it is semi-arboreal, omnivorous, and inhabits brushy and woody regions.

DESCRIPTION

Pelage:  P. leucopus is brownish to grayish depending on locality and often has a darker stripe down the middorsal line. The underside is white, as are the feet, but sometimes a buff or tan pectoral spot is present. The tail is bicolored like the body, while the ears are covered with short dark hairs.

Size:  The white-footed mouse is a medium size rodent like other common Peromyscus species, although size can vary widely (Hall, 1981 and others). The tail is nearly half the total length and the ears are average to large in size.

Weight: 10 to 43 g.

Measurements:  Adult measurements (in mm). Total length, 130 to 205; length of tail, 45 to 100; hindfoot length, 17 to 25; ears, 13 to 14; skull length, 24.0 to 29.5.

FORMAL DIAGNOSIS

A small to medium species of Peromyscus, the white-footed mouse is brownish to grayish dorsally with darker middorsal stripe often present. It is whitish ventrally with hairs having dark bases. A huffy pectoral spot is often present.  The ears are average in size and covered with short dark hairs. The feet are white dorsally with six plantar tubercles.  The tail is somewhat shorter to slightly longer than the head and body, usually moderately covered with dark dorsal and white ventral hairs.  It has one pair of pectoral and two pairs of inguinal mammae. The skull is small with no interorbital shelf or ridging.  The auditory bullae and the rostrum are not inflated.  The toothrows are parallel or are diverging anteriorly.  The styles of teeth are variable but accessory lophs are usually present.  The anterocone is usually undivided.  The baculum is elongate and having a broad base and a relatively large cartilaginous tip.  The glans penis bears well-developed spines and a long protractile tip having a pair of dorsal lappets.  A full complement of male accessory glands are present but the preputial glands are not visible macroscopically.  The sperm is typical of the genus. The stomach is discoglandular (Carleton, 1973; Hall, 1981; Hooper, 1957, 1958; Linzey and Layne, 1969, 1974).

Various combinations of mensural characters and of those described in the diagnosis distinguish P. leucopus from most species of the genus within its range. External characters alone are usually sufficient to distinguish P. leucopus from all other species of Peromyscus except P. maniculatus, P. polionotus, and P. gossypinus (Hall, 1981).

In Illinois, the longer and wider calcaneum of P. leucopus was distinguishable from that of P. maniculatus in all instances (Stains, 1959). Guilday and Handley (1967) reported that in unworn lower first molars the anteroconid in P. leucopus was symmetrical, whereas in P. maniculatus the labial side of the anteroconid was not well developed. In Chihuahua, Mexico, Anderson (1972) could best distinguish P. leucopus from P. maniculatus by total length, maximum length of the incisive foramen, and the pterygoid fossa. Aquadro and Patton (1980) provided positive identification of live individuals of P. leucopus and P. maniculatus in areas of sympatry based on the presence of salivary amylase electromorphs.

Discriminant functions based on various combinations of external and skull measurements have proved useful for separating specimens of P. leucopus and P. maniculatus, as demonstrated by Choate (1973) for populations from New England, by Choate et al. (1979) for those from Kansas, by Stromberg (1979) for those from Wisconsin, and by Thompson and Conley (1983) for those from New Mexico.

Linzey et al. (1976) employed a combination of measurements, with emphasis on length and width of anterior palatine foramina, length of hindfoot, and skull length, for separating P. leucopus from P. gossypinus. Martin (1967) was partly successful in separating the species by comparison of mandibular dimensions. Possible hybridization compounds the task of positively identifying all specimens in collections (Dice, 1937; McCarley, 1954), especially those without chromosomal or biochemical data.

The skull of P. leucopus lacks supraorbital ridges and inflated auditory bullae. The teeth possess accessory lophs, styles, and an undivided anterocone. The hyoid apparatus resembles that of other Peromyscus. No interspecific variation exists in the muscles of P. leucopus, P. maniculatus, and P. difficilis (all in the subgenus Peromyscus), but 17 differences occur between those of P. leucopus and P. eremicus (subgenus Haplomylomys). Organization of the carotid arteries in P. leucopus resembles closely that of other Peromyscus, especially P. maniculatus. The baculum and glans penis of P. leucopus resemble those of most other members of its subgenus, differing mainly in size (summarized primarily from Klingener's [1968] review). Linzey and Layne (1969) found that P. leucopus and P. gossypinus possess microscopic preputial glands; other species studied in the subgenus Peromyscus lacked these glands. In contrast, members of the subgenus Haplomylomys have well-developed, macroscopic preputials. P. leucopus spermatozoa resemble those of most other Peromyscus in having a recurved hook on the head (Linzey and Layne, 1974). The stomach of P. leucopus resembles that of most other Peromyscus in having a small glandular patch (discoglandular) with no pouch-like evagination (Carleton, 1973). Doty and Kart (1972) found midventral sebaceous glands in P. maniculatus and P. polionotus but not in P. leucopus, P. gossypinus, or other species studied.

 

 

DISTRIBUTION

The range of the white-footed mouse extends from southern Alberta, Saskatchewan, Maine, and Nova Scotia, southward through the eastern half of the United States to South Carolina, Georgia, and Alabama, and westward through New Mexico to central Arizona, thence southward through Chihuahua, Coahuila, and Durango and southward to the Yucatan Peninsula (Hall, 1981). The species is not recorded from the Gulf Coast Plain of North Carolina, South Carolina, Georgia, and Alabama or from any locality in Florida. A hiatus in the known range occurs in coastal Tabasco and in adjacent areas of Campeche and Veracruz in Mexico. Ranges of several insular and other mainland forms are partly or completely isolated from those of nearby populations.

HABITAT

Northern populations of this species reach highest densities in brushy fields and in woodlots dominated by deciduous trees but typically have low densities in grassy fields (Hamilton and Whitaker, 1979) and in mature, mainly coniferous forests (Choate, 1973). In eastern Texas, McCarley (1963) found that P. gossypinus apparently excluded P. leucopus from lowland habitats that P. leucopus occupies in regions further west where P. gossypinus is absent. In regions characterized by prairie or semi-desert, the white-footed mouse usually is most abundant in riparian areas and in ravines (Blair, 1954; Kaufman and Fleharty, 1974; Wilson, 1968). The habitat of P. leucopus typically includes a canopy (if only of brush), woody debris, and often rocks (Barry and Francq, 1980; Van Deusen and Kaufman, 1977). In Tamaulipas, Mexico, Alvarez (1963) commonly found P. leucopus in forested and brush habitats throughout the state under 365 m. In Veracruz, P. leucopus was found primarily in fields of brush and weeds and in sugar cane fields but not in tall grass; other habitats included newly cleared areas with fallen logs. In that area, P. leucopus "rarely enters deep forest" (Hall and Dalquest, 1963:303). Lackey (1978b) reported similar habitat use by populations in Campeche in the southern part of the Yucatan Peninsula, but Birney et al. (1974) reported P. leucopus as common in second-growth thorn forest and in fields planted to henequen in the northern part.

The population dynamics of P. leucopus do not differ consistently or dramatically from those of other species of Peromyscus (Terman, 1968). The genus as a whole is characterized by less variation in population density than that reported for a variety of other small terrestrial mammals such as Microtus pennsylvanicus and Reithrodontomys megalotis (Terman, 1966).

Home range size varies seasonally, with the largest areas recorded during the breeding season and the smallest during winter. Estimates of home-range size vary greatly; the average is approximately 0.1 ha. Males usually have larger home ranges than females although exceptions have been reported (Stickel, 1968). Other variables affecting home-range size include food supply, age, and population density (Stickel, 1968).

Population regulation in P. leucopus under various environmental and demographic conditions was attributed to food limitation (Bendell, 1959); to spatial limitations imposed by territoriality, especially among resident breeding females (Burt, 1940; Metzgar, 1971); and possibly to a reduction in recruitment of breeding-aged individuals caused by a decline in reproductive activity or to reduced juvenile survivorship, as suggested by Terman (1965) for P. m. bairdii. These studies suggest that population regulation mechanisms are effective only at relatively high population densities. Replacement in depopulated areas may occur through adjustment in boundaries of nearby territories and by immigration of transient mice when the population density of residents is low (Metzgar, 1971; Stickel, 1946).

Mortality in this species usually leads to a complete population turnover annually, although there may be seasonal differences in mortality (Snyder, 1956); a reliable measure of mortality is difficult to obtain because of the possibility of disappearance of individuals through emigration (Terman, 1968). Winter mortality may be relatively low compared with that in spring and summer (Lackey, 1973). Snyder (1956) reported an inverse relationship between population density and mortality in a Michigan population but could not identify causative factors.

NATURAL HISTORY

Feeding:  Insects were the most frequently occurring food class in stomach contents of P. leucopus throughout the year in a study in New York; starchy matter (mast, seeds) and green vegetation followed in frequency in late fall and winter, whereas fruit was next after insects in frequency in spring and summer. All other items occurred in a frequency less than 10% (Hamilton, 1941). In Indiana, seeds, insects, and unidentified vegetation occurred most frequently, representing 43%, 30%, and 25% of the diet, respectively, on a volume basis (Whitaker, 1966). Cultivated foods and grass seeds appear to be used infrequently in Indiana, even in non-forest habitats (Mumford and Whitaker, 1982). In an Illinois forest, seeds were the principal items consumed in spring and autumn but in summer and fall arthropods were the most frequent (Batzli, 1977). The ratio of the lengths of the small intestine to the hindgut and the ratio of the mucosal surface area of the small intestine to that of the hindgut of P. leucopus point to an omnivorous diet. In these characteristics, P. leucopus ranked between largely herbivorous Microtus and largely insectivorous and carnivorous Blarina (Barry, 1977).

Food-hoarding behavior was reported to be well developed in P. leucopus (Hamilton and Whitaker, 1979; Mumford and Whitaker, 1982) but was minimal in other studies (Lanier et al., 1974; Nicholson, 1941). P. leucopus shows greater flexibility in feeding behavior compared with P. maniculatus (Drickamer, 1972). Laboratory measurement of feeding diversity of field-caught white-footed mice indicates that immigrant mice consume a wider range of foods than residents (Tardif and Gray, 1978).

Nesting:  In some parts of its range, P. leucopus spends most of its active period on the ground, even in wooded habitat (Madison, 1977). Studies of nest-site selection by use of nest boxes in the field (Nicholson, 1941) and laboratory (Stah, 1980) suggest that P. leucopus usually select nest sites off the ground, but there are reports of nests at or near ground level in rock piles, logs, stumps, under trees, and in ground burrows (Mumford and Whitaker, 1982), including those of woodchucks (Marmota monax; Madison, 1977). In Veracruz, Mexico, nests were found under loosened bark of fallen trees (Hall and Dalquest, 1963). Wolff and Hurlbutt (1982) located nesting sites of P. leucopus noveboracensis and P. maniculatus aubiterrae by radiotelemetry and demonstrated that P. leucopus used ground nests significantly more often than P. maniculatus.

Nests built by white-footed mice consist of a variety of materials, including grass, leaves, hair, feathers, milkweed floss, shredded bark, and moss (Edwards and Pitts, 1952; Nicholson, 1941). Nest building by mice from various latitudes seems correlated with average midwinter temperatures at those latitudes (King et al., 1964). Nest-building behavior was most intense at a T,, of 5°C, and the most effective nest contained 13 g of nesting material, resulting in an energy saving of 5.1 Kcal/day at a T,, of 5°C (Glaser and Lustick, 1975). Hill (1972) found a positive correlation between the degree of maternal care of nestling young and the TB of the young. Significant differences in measures of nest-building activity between P. leucopus and Podomys floridanus were correlated with differences in diversity of habitats and nest sites used by the two species (Layne, 1969). Microhabitat features affect nesting behavior more than direct climatic effects (Layne, 1969; Wolfe, 1970). P. leucopus maintained under a short photoperiod build larger nests than those under a longer photoperiod (Lynch, 1974).

Activity:  White-footed mice are considered semi-arboreal because of their climbing in trees (Batzli, 1977; Nicholson, 1941) and possession of various arboreal adaptations. The tail is used as a prop and balancing organ during climbing. P. leucopus is more adept in crossing gaps and moving along narrow branches, can climb smoother tree trunks, and remains longer on an elevated platform with no pathway to the ground than various short-tailed, terrestrial species of Peromyscus. Tail amputation reduced climbing ability of white-footed mice more than in terrestrial species (Horner, 1954). White-footed mice are better than Clethrionomys gapperi at climbing vertically and traversing a 5 mm diameter dowel (Getz and Ginzberg, 1968), but score lower than P. gossypinus in laboratory measures of climbing (Dewsbury et al., 1980).

Orr (1959) found that individuals in an outdoor enclosure were more active at higher temperatures and relative humidities. P. leucopus in laboratory trials selected a higher mean floor temperature (32.4 + 1.3°C) than Mus musculus, P. maniculatus gracilis, or P. maniculatus bairdii (Ogilvie and Stinson, 1966). White-footed mice in Massachusetts were captured significantly more often than deer mice at higher temperatures and relative humidities, under overcast skies, and during light rain at night (Drickamer and Capone, 1977).

Behavioral regulation of population density in P. leucopus is supported by both field and laboratory studies. During the breeding season, home ranges of mice of the opposite sex overlap more than those of the same sex (Ormiston, 1983). Also, the frequency of establishment of home ranges by introduced subadult females was correlated negatively with density of resident adult females.  The trend between introduced subadult males and the density of adult males was similar but not significant (Metzgar, 1971). In laboratory trials, breeding females, but not males, behaved aggressively toward 21- to 25-day-old conspecifics (Rowley and Christian, 1976a). Laboratory observations (Hill, 1977; Vestal, 1977) suggest that avoidance behavior may be involved in behavioral population regulation. Evidence for the occurrence of social interactions and dominance relationships under natural conditions is suggested by the observation of Vestal and Hellack (1978) that field-caught neighbors seem to recognize each other and show submissive behavior in laboratory encounters. Kin recognition was reported by Grau (1982). Repulsion of individuals can occur without direct contact and could be based on olfactory or other sensory modalities (Mazdzer et al., 1976, Orr, 1959). Sexual maturation of P. leucopus in the laboratory is delayed by the presence of urine or feces of conspecifics (Rogers and Beauchamp, 1976).

Getz (1969) concluded there was no evidence that aggression was a determinant of habitat segregation between P. leucopus and Clethrioaomys gapperi. Increasing population density of Microtus pennsylvanicus in an outdoor enclosure altered use of space by P. leucopus (Bowker and Pearson, 1975), although, in laboratory trials, white-footed mice were aggressive toward and dominant over this species (Baenninger, 1973; Rowley and Christian, 1976b). Dominance by P. leucopus and P. maniculatus reubiterrae tested in the field was site-specific rather than species-specific (Wolff et al., 1983).

Young P. leucopus probably begin exploration of the area surrounding their birthsite between 16 and 25 days of age (Sheppe, 1966), and females abandon litters 20 to 40 days postpartum (Nicholson, 1941). Most juveniles initially disperse within a radius of about 100 m of their point of origin, but longer movements approaching 1 km also occur (Ormiston, 1983; Stickel and Warbach, 1960). Adults may make long distance movements during exploration or changes in location of home range (Ormiston, 1983). P. leucopus can cross bodies of water by crossing on ice or by swimming. Individuals have well-developed swimming abilities (Evans et al., 1978; King et al., 1968) and pass between islands up to 233 m apart (Sheppe, 1965).

Peromyscus leucopus is thoroughly familiar with its immediate environment and with those features that may be used in navigation, such as trees, logs, rocks, and other objects (Barry and Francq, 1980). Individuals orient toward trees that are proximally associated with a goal (Joslin, 1977). P. leucopus uses visual and olfactory cues to orient and home (Parsons and Terman, 1978). Population density and activity were positively related to measures of shrub cover or stem density in some studies (Kaufman and Fleharty, 1974; M'Closkey and Fieldwick, 1975; Stickel and Warbach, 1960), negatively related in some (Barry and Francq, 1980; Bongiorno and Pearson, 1964), and without relationship in others (Getz, 1961; Klein, 1960).

Peromyscus leucopus responds strongly to new objects placed within a familiar area, which may facilitate learning of new escape routes, feeding sites, nests, potential mates, and home-range areas. White-footed mice show weak neophobia, followed by neophilia that declines progressively (Sheppe, 1966).

Circadian Rhythm:  Peromyscus leucopus is primarily nocturnal (Baumgardner et al., 1980) but occasionally is active during day in winter (Mumford and Whitaker, 1982).

Breeding:. The minimum gestation period of non-lactating females is 22 to 23 days (Svihla, 1932). Among lactating females, gestation is extended as much as 14 days (Svihla, 1932), possibly from a delay in blastocyst implantation induced by effects of lactation and nursing on hormones controlling implantation, as in Rattus (Zeilmaker, 1964). Compared with P. leucopus from Michigan, those from southern Mexico exhibited a shorter gestation period. Among lactating females, there was no correlation between the number of young being nursed and the duration of the gestation period of the next litter; litter size and length of gestation period of that litter were not correlated in either population (Lackey, 1978a).

Mean litter size in P. leucopus is 5.0 in Ontario (Coventry, 1937), 4.3 in Michigan (Lackey, 1978a), 3.7 in Missouri (Brown, 1964), and 3.5 in southern Texas (Guetzow and Judd, 1981), and 3.0 for eight specimens from northern Tamaulipas, Mexico. The apparent latitudinal trend is reversed in southern Mexico where litter size was 5.4 for females trapped in December and January; in August, however, litter size was 3.9 (Lackey, 1978a). Seasonal variation in mean litter size was not considered a consequence of variation in age and body size of females. Davis (1956) found that litter size in a New Jersey population varied with age and body size of breeding females.

The breeding season in northern populations is strongly seasonal, with peaks in spring and late summer in Michigan (Burt, 1940), whereas in southern Texas (Judd et al., 1978) and in the state of Campeche, Mexico (Lackey, 1978a) the breeding season is year-round. Lower frequencies of pregnant females in northern populations during midsummer were interpreted as a reflection of many young females in the population (Cornish and Bradshaw, 1978; Long, 1973) or cessation of reproductive activity by all females (Burt, 1940). The male reproductive cycle in northern populations exhibits a seasonal pattern similar to that of females (Cornish and Bradshaw, 1978).

Post-natal development was described by Layne (1968), and extensive observations and measurements were reported by Lackey (1973, 1978a) for laboratory stocks derived from populations from Mexico and Michigan.  Females from Mexican stock averaged becoming sexually mature at 37.7 days, compared with 44.4 days for Michigan mice, but males exhibited no significant differences in rate of sexual development.

Postnatal growth in P. leucopus is rapid and largely completed within 6 weeks of birth. Postnatal growth in a population from southern Texas (Guetzow and Judd, 1981) and from a population in southern Mexico (Lackey, 1978a) were similar in most respects, suggesting little geographic variation in rates of growth. However, effects of litter size on postnatal growth rates were substantially greater in mice from Michigan than in those from southern Mexico.

The estrous cycle of P. leucopus resembles that of some other species of this genus, such as P. californicus, P. crinitus, and P. eremicus, in having a mean duration of 6.0 days (Dewsbury et al., 1977). Ovulation is spontaneous, but pseudopregnancy can be induced (Conaway, 1971). Vaginal smears resemble those of laboratory strains of Rattus and Mus (F. L. Osgood, Jr., cited in Asdell, 1964). There is a postpartum estrus (Svihla, 1932) during which a single copulation usually results in pregnancy under laboratory conditions (Dewsbury et al., 1979).  Resorption of embryos in P. leucopus is infrequent but transmigration of blastocysts was noted in 24% of litters in Missouri (Brown, 1964).

The pattern of copulatory behavior shown by P. leucopus consists of no locking or intravaginal thrusting, with multiple intromissions before ejaculation and multiple ejaculations (Dewsbury, 1975a). Latency to initiate copulation is long, and the number of ejaculations before satiety and frequency of intromissions before first ejaculation is low compared with those of many other cricetids (Dewsbury, 1975b). The natural fertility rate in this species is low (Dewsbury and Lanier, 1976). A copulatory plug is found in the female after mating, which may reduce sperm competition or prevent sperm leakage (Baumgardner et al., 1982; Voss, 1979). P. leucopus probably are polygamous (Myton, 1974). In the laboratory, both sexes participate in parental care by sitting on pups and licking them (Hartung and Dewsbury, 1979), although females attend pups more frequently than males (McCarty and Southwick, 1977). In forest enclosures and in the laboratory, pups in the company of their mothers maintained homeothermic temperatures irrespective of their ability to thermoregulate when alone (Hill, 1972). The extent and significance of parental care in the wild is unknown.

KARYOLOGY

Peromyscus leucopus has a diploid chromosome number of 48 and a fundamental number of 70 to 72 (Hsu and Arrighi, 1968). Two distinct karyotypes occur, one in northeastern and north-central, and the other in southwestern United States (Baker et al., 1983; Robbins and Baker, 1981). The two races differ by three euchromatic pericentric inversions, a difference greater than that distinguishing various pairs of closely related species of Peromyscus (Robbins and Baker, 1981). Individuals from Tennessee, Oklahoma, and Mississippi exhibit karyotypes intermediate between the two types, suggesting the existence of an extensive area of hybridization between the two karyotype races. There is a greater similarity in karyotype between the northeastern race of P. leucopus and the cotton mouse, P. gossypinus, than between the two chromosomal races of P. leucopus (Baker et al., 1983). The karyotype of Latin American populations remains unknown.

GENETICS

Genetic differences between geographically close populations of P. leucopus often are observed (Bokoch and Eckroat, 1976; Price and Kennedy, 1980). Browne (1977) analyzed protein variation at 28 loci and found that the Bass Island populations in Lake Erie differed from mainland samples in exhibiting lower average individual heterozygosity and a lower proportion of polymorphic loci.

CLASSIFICATION

Order Rodentia, Suborder Myomorpha, Family Muridae, Subfamily Sigmodontinae, Tribe Peromyscini,  Genus Peromyscus, Subgenus Peromyscus, leucopus-species group.

SUBSPECIES

Hall (1981) recognized 17 subspecies, as follows:

P. l. affinis (J. A. Allen, 1891b), see above (musculoides Merriam a synonym).

P. 1. ammodytes Bangs, 1905. Type locality Monomoy Island, Barnstable Co., Massachusetts.

P. 1. aridulus Osgood, 1909. Type locality Fort Custer, Big Horn Co., Montana.

P. 1. arizonae (J. A. Allen, 1894). Type locality Fairbank, Cochise Co., Arizona.

P. 1. castaneus Osgood, 1904. Type locality Yohaltun, Campeche, Mexico.

P. 1. caudatus Smith, 1939. Type locality Wolfville, Kings Co., Nova Scotia, Canada.

P. 1. cozumelae Merriam, 1901, see above.

P. l. easti Paradiso, 1960. Type locality 6.8 mi SE Pungo, Princess Anne Co., Virginia.

P. 1. fuses Bangs, 1905. Type locality West Tisbury, Martha's Vineyard, Dukes Co., Massachusetts.

P. 1. incensus Goldman, 1942. Type locality Metlaltoyuca, 800 ft, Puebla, Mexico.

P. l. lachiguiriensis Goodwin, 1956. Type locality San Jose Lachiguiri, about 4,000 ft, Oaxaca, Mexico.

P. l. leucopus (Rafinesque, 1818), see above (brevicaudus Davis a synonym).

P. l. mesomelas Osgood, 1904. Type locality Orizaba, Veracruz, Mexico.

P. 1. noveboracensis (Fischer, 1829). Type locality New York (myoides Gapper, emmonsi DeKay, arboreus Gloger, michiganensis Audubon and Bachman,

campestris Le Conte, and minnesotae Mearns are synonyms).

P. 1. ochraceus Osgood, 1909. Type locality Winslow, Navajo Co.,  Arizona.

P. 1. texanus (Woodhouse, 1853), see above (mearnsi J. A. Allen and canus Mearns are synonyms).

P. 1. tornillo Mearns, 1896, see above (flaccidus J. A. Allen a synonym).

TAXONOMIC  HISTORY

Musculus leucopus Rafinesque, 1818:446. Type locality pine barrens of Kentucky. Apparently restricted

by Osgood (1909: 115-116) to the mouth of the Ohio River.

Peromyscus leucopus Thomas, 1895:192; first use of current name combination.

Cricetus myoides Gapper, 1830:204. Type locality between York and Lake Simcoe, Ontario, Canada.

Arvicola emmonsi DeKay, in Emmons, 1840:61. Type locality Massachusetts.

Peromyscus arboreus Gloger, 1841:95. Type locality unknown.

Mus michiganensis Audubon and Bachman, 1842:304. Type locality Erie Co., Michigan (=Ohio).

Hesperomys campestris Le Conte, 1853:413. Type locality New Jersey.

Hesperomys texana Woodhouse, 1853:242. Type locality vicinity of Mason, Mason Co., Texas.

Yesperimus mearnsi J. A. Allen, 1891a:300. Type locality Brownsville, Cameron Co., Texas.

Hesperomys afnis J. A. Allen, 1891b:195. Type locality Barrio, Oaxaca, Mexico.

Peromyscus canus Mearns, 1896:445. Type locality Fort Clark, Rinney Co., Texas.

Peromyscus tornillo Mearns 1896:445. Type locality Rio Grande, 6 mi above El Paso, El Paso Co., Texas.

Peromyscus musculoides Merriam, 1898:124. Type locality Cuicatlan, Oaxaca, Mexico.

Peromyscus cozumelae Merriam, 1901:103. Type locality Isla Cozumel, Yucatan, Mexico.

REFERENCES

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ALLEN, J. A.  1891b.  Description of two supposed new species of mice from Costa Rica and Mexico, with remarks on Hesperomys melanophrys of Coues. Proc. U.S. Natl. Mus., 14:195196.

ALLEN, J. A.  1894.  Description of ten new North American mammals, and remarks on others. Bull. Amer. Mus. Nat. Hist., 6: 317-332.

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ANDERSON, S.  1972.  Mammals of Chihuahua taxonomy and distribution. Bull. Amer. Mus. Nat. Hist., 148:151-410.

AQUADRO, C. F., AND J. C. PATTON.  1980.  Salivary amylase variation in Peromyscus: use in species identification. J. Mamm., 61:703-707.

ASDELL, S. A.  1964.  Patterns of mammalian reproduction. Cornell Univ. Press, Ithaca, New York, 670 pp.

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BANGS, 0.  1905.  Notes on deer mice (Peromyscus) of some of the islands of the southern New England coast. Proc. New England Zool. Club, 4:11-15.

BARRY, R. E., JR.  1977.  Length and absorptive surface area apportionment of segments of the hindgut for eight species of small mammals. J. Mamm., 58:419-420.

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BATZLI, G. O.  1977.  Population dynamics of the white-footed mouse in floodplain and upland forests. Amer. Midland Nat., 97:18-32.

BAUMGARDNER, D. J., S. E. WARD, AND D. A. DEWSBURY.  1980.  Diurnal patterning of eight activities in 14 species of muroid rodents. Anim. Learn. Behav., 8:322-330.

BAUMGARDNER, D. J., T. G. HARTUNG, D. K. SAWREY, D. G. WEBSTER, AND D. A. DEWSBURY.  1982.  Muroid copulatory plugs and female reproductive tracts: a comparative investigation. J. Mamm., 63:110-117.

BENDELL, J. F.  1959.  Food as a control of a population of whitefooted mice, Peromyscus leucopus noveboracensis (Fischer). Canadian J. Zool., 37:173-209.

BIRNEY, E. C., J. B. BOWLES, R. M. TIMM, AND S. L. WILLIAMS.  1974.  Mammalian distributional records in Yucatan and Quintana Roo, with comments on reproduction, structure, and status of peninsular populations. Occas. Papers Bell Mus. Nat. Hist., Univ. Minnesota, 13:1-25.

BLAIR, W. F.  1954.  Mammals of the mesquite plains biotic district in Texas and Oklahoma, and speciation in the central grasslands. Texas J. Sci., 6:235-264.

BOKOCH, G. M., AND L. R. ECKROAT.  1976.  An electrophoretic study of lactate dehydrogenase and esterase isozymes in the deer mouse, Peromyscus leucopus.  Proc. Pennsylvania Acad. Sci., 50:141-148.

BONGIORNO, S. F., AND P. G. PEARSON.  1964.  Orientation of Peromyscus in relation to chronic gamma radiation and vegetation. Amer. Midland Nat., 72:82-92.

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