Peromyscus yucatanicusYucatan deer mouse

Geographic Range

Yucatan deer mice, Peromyscus yucatanicus, are found in the Neotropical region limited to the Yucatan Peninsula. The northernmost extent of this species is southern Mexico, which includes the states of Yucatan, Quintana Roo, and north-central areas of Campeche. The furthest westward the deer mice have been recorded was Escarcega, Campeche, Mexico. On the Yucatan peninsula, Yucatan deer mice have been reported as far south as northern Guatemala and northern Belize. (Zarza, et al., 2003)


Yucatan deer mice have been reported to commonly inhabit a variety of forest types, which include semi-deciduous, evergreen, humid rainforests and secondary growth forests. They inhabit agricultural areas like banana (Musa) plantations and cornfields (Zea mays) of the Yucatan Peninsula. Removal of vegetation leaves these deer mice with limited to no protection, which leads to greater risk of predation. They are primarily terrestrial and can be found seeking shelter from predators along fallen logs, thick brush, low branches, and dense grass. They are found in a variety of elevations, ranging from sea level to 500 m. (; de Grammont and Cuarón, 2016; Lackey, 1978; ; Reid, 2009; Young and Jones Jr, 1983; Zarza, et al., 2003)

  • Range elevation
    0 to 500 m
    0.00 to 1640.42 ft

Physical Description

Deer mice have geographic variations in fur color from north to south on the Yucatan Peninsula. Yucatan deer mice reported further north have coats consisting of a brighter light-brownish-yellow to a pale orange-brown-colored fur on their dorsum while the ventral fur is a yellow-white. In mice further south, especially in Campeche, the upper parts of the dorsum are gray-brownish transitioning to a brown ochre on the sides with the ventral fur being a yellow-white. In addition, Yucatan deer mice throughout the Yucatan Peninsula have dusky hairs.

Ortega and Arita (2013) separate these color morphs by subspecies; Peromyscus yucatanicus yucatanicus has an ochre pelage, while Peromuscus yucatanicus badius has a darker brown dorsal pelage. Both subspecies have white bellies and white feet from the wrist/ankle to the toes.

There are three age-related fur colors. The juvenile coat is gray and replaced by the subadult coat; the dorsum during this latter stage is a dusky color while the ventral is a pale gray with a hint of yellow. The adult coat is a brighter brownish-yellow on the sides and dorsum and the ventral is a yellowish white. Males and females have different coat colors based on age. Adult males have a ventrum that is yellowish-white while the dorsum is a brighter brownish-yellow. Females in the subadult stage go through a post-subadult molt; the ventral is pale gray and the dorsum is dusky. Adults molt twice each year, once in spring and autumn.

The average weight of adults is 28 g ranging from 15 to 35g. Yucatan deer mice exhibit average total lengths of 201.7 mm (range 185 to 219 mm) in Yucatan and 190.9 mm (range 181 to 203 mm) in Campeche. Their tails are bicolored and nearly naked, being a dusky, grayish color on the dorsal side and yellow underneath. The average tail lengths are 99.8 mm (range 85 to 117 mm) in Yucatan and 94.5 mm (range 84 to 105 mm) in Campeche. The feet are white from the wrist and tarsus to the toes. The average hind feet lengths are 21.8 mm (range 20 to 24 mm) in Yucatan and 23.6 mm (range 23 to 24 mm) in Campeche. They have large, brown, naked ears ranging from 18 to 22 mm. Their dental formula is 1003/1003, 16 in sum. Their brain cases are long and narrow, while their auditory bullae and teeth are relatively small. Their eyes are narrow and have a dark orbital ring.

Yucatan deer mice differ from members of the genus Peromyscus because they have a moderately developed supraorbital ridge. (Lackey, 1976; Ortega and Arita, 2013; Young and Jones Jr, 1983)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • male more colorful
  • Range mass
    15 to 35 g
    0.53 to 1.23 oz
  • Average mass
    28 g
    0.99 oz
  • Range length
    181 to 219 mm
    7.13 to 8.62 in
  • Average length
    201.7 mm
    7.94 in


There are no studies of Yucatan deer mice mating behaviors in the wild. However, these mice have been kept in captivity and their behaviors are well-documented. In captivity, Dewsbury (1979) calculated the average time of copulation to be 285.5 seconds. After the females were introduced, the males mounted the females from behind, and internal fertilization was achieved due to a forceful inward pelvic thrust. Copulation lasted ca. 1 second. Single or multiple ejaculations were possible with each insertion. There was no record of the locking taking place. Out of forty-six copulation tests, the average number of matings per pair was six with an average break of 392.3 seconds between mating efforts. In captivity, Dewsbury (1979) did not specify if the females and males remained mates or if they mated with multiple partners. (Dewsbury, 1979; Young and Jones Jr, 1983)

In the wild, Yucatan deer mice breed year-round at lower latitudes due to the consistent climate and a possibility of more food sources throughout the year. Although breeding may occur year-round, reproduction is greatest during the wet season (June through September). When Lawlor (1965) trapped year-round, he caught pregnant females in April, July, August, and December, while lactating, non-pregnant females were caught in July and August. Juvenile mice were caught in March, July, August, November, and December. Birney et al. (1974) caught pregnant females in April and May. Lackey (1976) caught pregnant females in December and lactating, non-pregnant females in January, May, and December. Deer mice are viviparous and give birth to live offspring. Litter size ranges are typically 1 to 3 offspring but can increase to 5 with increasing age and larger body size. Lackey (1976) reported that the lowest average birth mass of offspring from a litter of five was 1.98 g. No other data were given on birth mass.

Gestation periods from initial copulation to birth averages 30 days. In already-lactating females, the gestation period is 31 to 33 days. Furthermore, females can experience lactation-induced delayed implantation and post-partum estrous, which is normal in the reproductive cycle. Because of these delays, time from mating to birth can be 36 days to 134 days. Non-lactating, pregnant females had cases in which the preceding litter was killed by the parents immediately after birth, with the shortest gestation period of 27 to 28 days. Weaning time and time to independence have not been recorded in the wild nor captivity.

Female deer mice reach sexual maturity, on average, when they are 51.5 days old. Sexual development in males is marked by the enlargement of testis and scrotum. There are two stages in which the size of the scrotum is classified: when the testes first appear to be scrotal and maximum scrotal size. Males reach sexual maturity after the augmentation of the scrotum and after the maximum scrotal size has been reached. The average age when the testes first appeared was 45 days, and the maximum scrotal size is 74.4 days. The first stage was reached at an average age of 41.5 days in males from litters of three. In litters of four, the average age was 47.7 days. Males from litters of three attained the maximum stage of scrotal development at an average age of 65.4 days whereas males from litters of four had an average age of 76.5 days. (Birney, et al., 1974; de Grammont and Cuarón, 2016; Lackey, 1976; Lawlor, 1965; Young and Jones Jr, 1983)

  • Breeding interval
    Yucatan deer mice breed throughout the year.
  • Breeding season
    Breeding occurs year round, reproduction is greatest during the wet season (June - September).
  • Range number of offspring
    1 to 5
  • Range gestation period
    27 to 33 days
  • Average gestation period
    31 days
  • Average age at sexual or reproductive maturity (female)
    51.5 days
  • Range age at sexual or reproductive maturity (male)
    41.5 to 76.5 days
  • Average age at sexual or reproductive maturity (male)
    65.4 days

There are no studies of Yucatan deer mice providing parental care in the wild or in captivity. Lackey (1976) reported that the deer mice offspring opened their eyes between 13 to 19 days of age and their ears opened between 11 to 17 days. It's suggested that females nurse their young due to observed lactating females, and is likely they care for their offspring because they are blind and deaf at birth. Females of the genus Peromyscus most often care for and nurse their young within the nest until they are weaned. The males protect them from possible predators. It is likely that parental care decreases with increasing litter size. (Lackey, 1976; Nowak, 1999)

  • Parental Investment
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female


As with most species of the genus Peromyscus, Yucatan deer mice have a relatively short lifespan, averaging one to two years. In the wild, life expectancy is shorter, usually less than a year, with a maximum of 1.5 years. (de Grammont and Cuarón, 2016)

  • Typical lifespan
    Status: wild
    1.5 (high) years
  • Average lifespan
    Status: wild
    1 years
  • Typical lifespan
    Status: captivity
    1 to 2 years


Yucatan deer mice live in colonies whose size depends on the availability of resources. In the wild, Pech-Canché et al. (2012) calculated the densities of the Yucatan deer mice in 3 forest types: medium semi-deciduous jungle, low flood forest (one that is flooded 4-6 months/year), and secondary forest. The average population density of deer mice in the jungle was the highest among the three habitats with 35.9 individuals/ha ± 6.8, and a fluctuation between 20 and 24 individuals/ha. In the low flood forest, the average density was 18.8 individuals/ha ± 4.9, with a fluctuation density of 9 to 25 individuals/ha. In the secondary forest, density averaged 16.9 individuals/ha ± 4.4 and a fluctuation of 6 to 20 individuals/ha. It is not known if they have a social system or if there's a social hierarchy established.

Communication in Yucatan deer mice hasn't been well researched. It is suggested that they communicate by using vocals, tactility, and chemicals. Mice produce ultrasonic vocalizations, squeaks, and shrieks. They also rapidly drum their feet and/or tail against a hard surface to produce vibrations, usually when they are being disturbed or trying to show aggression. Tactile communication involves grooming one another. Chemical communication involves producing a variety of scents.

Yucatan deer mice are nocturnal. They spend most of their time on the ground but are also able to climb. Chilpa‐Galván et al. (2017) reported that these deer mice climbed trees up to 2 m off the ground in order to forage on seeds. It is unknown if they construct their own burrows or use burrows pre-made by another animal. In captivity, Lackey (1976) reported that juveniles 3 to 6 weeks old developed aggressive behavior and attempted to bite when handled. Aggressive behavior declined with age with adults being more docile. (Chilpa‐Galván, et al., 2017; Lackey, 1976; Nowak, 1999; Pech-Canché, et al., 2012)

Home Range

Pech-Canché, et al. (2012) reported that the linear distance males travel from their burrows was 70 m to 80 m daily. Females traveled 48 m to 105 m daily. Territory size has not been quantified, but it is suggested that their territory size is outside and within their burrows. (Pech-Canché, et al., 2012; Young and Jones Jr, 1983)

Communication and Perception

Communication in Yucatan deer mice hasn't been well researched. Members of the genus Peromyscus can communicate by using vocals, visuals, tactility, and chemicals. Mice produce ultrasonic vocalizations, which are useful in situations where predators can’t hear the mice. Other vocalizations involve squeaks and shrieks. They also rapidly drum their feet and/or tail against a hard surface to produce vibrations, usually when they are being disturbed or trying to show aggression. They communicate visually using posture. Tactile communication involves grooming one another and chemically they produce a variety of scents. It's likely that Yucatan deer mice used these types of communication. (Nowak, 1999)

Food Habits

Yucatan deer mice are granivores and their diet is mostly based on grains, seeds, and fruit. There is no current research on their food habits in nature but while being studied in captivity they were fed Teklad Hamster Chow, which is made up primarily of soybeans (Glycine max), corn (Zea mays), and wheat (Triticum). For other studies in the wild, traps were baited with peanut butter, raisins, oats, and bacon. It is also suggested that they fed off the vegetation from farms if they were inhabiting a banana, Musa, plantation or cornfields. (Lackey, 1976; Lackey, 1978; ; Zarza, et al., 2003)

  • Plant Foods
  • seeds, grains, and nuts
  • fruit


Although there is no information regarding predators specific to Peromyscus yucatanicus, it is suggested that mammalian predators may include gray foxes (Urocyon cinereoargenteus), long-tailed weasels (Mustela frenata), greyheaded tayra (Eira barbara), and greater grison (Galictis vittata). Yucatan deer mice are primarily terrestrial and seek shelter from predators along fallen logs, in thick brush, in low branches, in dense grass and within burrows. Their pelage color provides camouflage, decreasing risk of predation. (Birney, et al., 1974; de Grammont and Cuarón, 2016)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Yucatan deer mice are granivores whose diet mostly consists of grains, seeds, and fruit. They contribute to seed dispersal via consumption of a variety of plants. They can also co-exist with other species such as white-footed mice, Peromyscus leucopus. Lackey (1976) reported that Yucatan deer mice dominated over white-footed mice when they are within close range of each other. Additionally, Yucatan deer mice play a role in sustaining predator populations. Due to their larger size and slower movements, they are open to greater risk of predation compared to smaller prey.

Yucatan deer mice are the second most abundant cricetid rodent in the endemic area of localized cutaneous leishmaniasis and the highest widespread vector of natural infection by Leishmania mexicana. This parasite is spread when infected female phlebotomine sandflies bite an organism. Peniche-Lara et al. (2015) reported that cat-flea typhus (Rickettsia felis) was detected in the ectoparasite cat flea, (Ctenocephalides felis), parasitizing a wild Yucatan deer mouse. Zavala-Velaquez et al. (1996) reported that wild Yucatan deer mice tested positive for Chagas disease (Trypanosoma cruzi). (Chilpa‐Galván, et al., 2017; Lackey, 1976; Peniche-Lara, et al., 2015; Zavala-Velaquez, et al., 1996)

  • Ecosystem Impact
  • disperses seeds
Commensal/Parasitic Species
  • cat flea (Ctenocephalides felis)
  • leishmania (Leishmania mexicana)
  • cat-flea typhus (Rickettsia felis)
  • Chagas disease (Trypanosoma cruzi)

Economic Importance for Humans: Positive

Yucatan deer mice are one of the primary reservoirs of Leishmania mexicana. Loría-Cervera et al. (2018) conducted an experiment to study localized cutaneous leishmaniasis caused by Leishmania mexicana. This experiment showed that the mice can produce the same clinical signs and the immune response observed in humans that is caused by leishmaniasis. The immune response associated with control and pathogenesis of diseases are like a human’s infection outcomes, which includes asymptomatic infection. Bettering our knowledge of immunological mechanisms associated with resistance to Leishmania mexicana could lead to a vaccine to help control cutaneous leishmaniasis. (Loría-Cervera, et al., 2018; Nalleli Loría-Cervera, et al., 2013; Sosa-Bibiano, et al., 2012)

Economic Importance for Humans: Negative

Yucatan deer mice are the second most abundant cricetid rodent in the endemic area of localized cutaneous leishmaniasis and have the highest widespread natural infection by Leishmania mexicana. It is spread when infected female phlebotomine sandflies bite an organism. Cutaneous leishmaniasis causes skin sores. Visceral leishmaniasis affects several internal organs like the spleen, liver, and bone marrow. People usually develop fever, weight loss, swelling of the spleen and liver, and abnormal blood tests. People may have low blood counts, including a low red blood cell count and a low white blood cell count. Peniche-Lara et al. (2015) reported that Rickettsia felis was detected in one of the four ectoparasites, cat fleas Ctenocephalides felis, parasitizing a wild Yucatan deer mouse. Rickettsia typhi causes headaches, fever, rashes and can lead to multisystem diseases, including infection of the brain, lung, liver, kidney, and heart. The infection spreads when fleas or ticks bite or excrete on the skin. Cases of infections are in places that are associated with rodent presence. People who work in agriculture and livestock, have a close proximity to vegetation, domestic, and wild animals around their houses. (Loría-Cervera, et al., 2018; Nalleli Loría-Cervera, et al., 2013; Peniche-Lara, et al., 2015; Sosa-Bibiano, et al., 2012)

Conservation Status

Yucatan deer mice are an abundant, stable species and are currently classified as a species of "Least Concern" on the IUCN's Red List of Threatened Species. These mice have no special status on the US Federal List, CITES Appendices, and the State of Michigan List. Although they are fairly limited in geographic range, there are no major threats to this species. Therefore, there are no conservation measures for this species. They occasionally inhabit protected areas within their geographic range. (de Grammont and Cuarón, 2016)


Anastasia Mejia (author), Radford University, Layne DiBuono (editor), Radford University, Lindsey Lee (editor), Radford University, Kioshi Lettsome (editor), Radford University, Karen Powers (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.



living in the southern part of the New World. In other words, Central and South America.

World Map


living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

causes disease in humans

an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).


uses smells or other chemicals to communicate


used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.


having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

delayed implantation

in mammals, a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months.


a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females


union of egg and spermatozoan


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


an animal that mainly eats fruit


an animal that mainly eats seeds


An animal that eats mainly plants or parts of plants.

induced ovulation

ovulation is stimulated by the act of copulation (does not occur spontaneously)


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


Living on the ground.


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year


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