The earliest fossils of existing neotomine genera are from the late Miocene of North America.
Neotomines have acute senses of smell, touch, hearing, and vision. They communicate with a variety of calls, chirps, and even miniature "wolf" howls. Some neotomines communicate with ultrasounds (Smith 1972), and they occasionally drum their front feet rapidly on the ground when alarmed. Chemical signaling with pheromones and scent marks is an extremely important aspect of communication in this group, as these odors can quickly send a signal about the identity and status of an individual (Ma et al. 1999).
Communication Channels: acoustic ; chemical
Other Communication Modes: pheromones ; scent marks
Perception Channels: visual ; tactile ; acoustic ; ultrasound ; chemical
The IUCN lists 15 neotomine species as lower risk, 9 species as vulnerable, 13 species as endangered (6 Neotoma species, 5 Peromyscus species, Jico deer mice, Habromys simulatus, and Cozumel harvest mice, Reithrodontomys spectabilis), and 2 species as critically endangered (Slevin's mice, Peromyscus slevini, and false canyon mice, Peromyscus pseudocrinitus, both of Mexico). In addition, one species has gone extinct recently (Pemberton's deer mice, Peromyscus pembertoni, from San Pedro Nolasco Island in Mexico). Many neotomine species have small, restricted ranges, narrow habitat requirements, and are threatened by encroaching human development.
Neotominae is a large New World subfamily of rat-like or mouse-like cricetid rodents. This group includes the packrats and woodrats, as well as the familiar deer and white-footed mice. There are 124 neotomine species in 16 genera, distributed among four tribes.
Some neotomines are vectors of human diseases, including hantavirus and lyme disease. Also, they are considered nuisance animals when they enter homes, raid food stores, gnaw on household goods, and build nests in unwelcome places.
Negative Impacts: injures humans (carries human disease); household pest
Neotomines are bred in captivity and used as lab animals for genetic and physiological research.
Positive Impacts: research and education
Neotomines are primary and higher-level consumers, and they are a staple food source for various predators. Also, they impact forest regeneration by consuming seeds and tree seedlings (Cote et al. 2003) and they may be important dispersers of mycorrhizal fungi (Mangan and Adler 2000). Finally, neotomines are parasitized by ticks and mites, fleas, lice, bot flies, nematodes, and flukes (Kinsella 1991).
Commensal/Parasitic Species:
Neotomines range from herbivorous to carnivorous in their eating habits. Foods consumed include seeds, roots, stems, cacti, pine needles, leaves, nuts, fungi, insects, scorpions, other rodents, and carrion. Many store food inside of their burrows for later consumption.
Foraging Behavior: stores or caches food
Primary Diet: carnivore (Eats terrestrial vertebrates, Insectivore , Eats non-insect arthropods, Scavenger ); herbivore (Folivore , Frugivore , Granivore ); omnivore ; mycophage
Neotomines are distributed throughout North America, from Panama to Alaska and northern Canada.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
These rodents occupy a wide variety of habitats, including prairies, savannahs, mountains, deserts, marshes, agricultural fields, suburban human dwellings, forest edges, scrub forests, rainforest, coniferous forest, and temperate and tropical deciduous forest.
Habitat Regions: temperate ; tropical ; terrestrial
Terrestrial Biomes: taiga ; desert or dune ; savanna or grassland ; chaparral ; forest ; rainforest ; scrub forest ; mountains
Wetlands: marsh ; swamp ; bog
Other Habitat Features: suburban ; agricultural ; riparian
Most neotomines do not live more than a year in the wild. The record lifespan in captivity is eight years, five months.
Neotomines are mouse-like or rat-like in overall appearance, with long tails and prominent ears. Their head and body length ranges from 50 to 351 mm, and their tails range from 35 to 240 mm. They weigh 6 to 450 grams. In some species, males weigh more, and are sometimes longer than females (Schulte-Hostedde et al. 2001). Male neotomines often have prominant ventral sebaceous glands, but they usually lack rump, hip, and flank glands. The pelage is usually dense, ranges from short to long, and can be either coarse or soft. Neotomines range in color from pale to very dark, and they are yellowish, reddish, brown, or gray on their dorsal surface and buffy, grayish, reddish, or white below. Some populations consist of more than one color morph (Smith 1972). The tail is sparsely haired or bushy with a tufted tip and ranges from long and skinny to short and fat. The large ears are usually sparsely haired.
The neotomine dental formula is 1/1, 0/0, 0/0, 3/3 = 16. The incisors are usually orthodont or opisthodont, and the molars are rooted and have a biserial cusp arrangement (in contrast to the triserial cusp arrangement of most murines). Each molar has a longitudinal enamel crest (mure or murid). The molars range from brachydont to hypsodont, and the third molars are usually smaller than the second molars. Neotomine skulls have flat or slightly recessed pterygoid fossae, and small to medium-sized auditory bullae. In addition, the mastoid bullae are not hypertrophied, and an accessory tympanum is always present. The malleus is of parallel construction. Other neotomine skull characteristics vary widely. A skeletal characteristic shared by most neotomines is the presence of a prominant neural spine on the second thoracic vertebra. Finally, neotomines have one- or two-chambered stomachs, and the tongue bears a single circumvallate papilla.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry ; polymorphic
Sexual Dimorphism: sexes alike; male larger
These rodents are preyed upon by a variety of other animals, including hawks, owls, snakes, and carnivorous mammals. Neotomines may avoid predation by decreasing their activity level on bright, moonlit nights (Topping et al. 1999), and by having fur that matches their background (Kaufman 1974). Additionally, some neotomine species have tails that break off easily when grabbed, allowing escape.
Known Predators:
Anti-predator Adaptations: cryptic
Many neotomines are promiscuous, and males and females only associate for the brief time required for mating. Others are polygynous or monogamous. In some species, a copulatory plug forms during mating and seals the female's reproductive tract, hindering the success of matings with other males.
Mating System: monogamous ; polygynous ; polygynandrous (promiscuous)
Neotomines are capable of reproducing year round, although for some populations there is a decline in reproduction during the winter months and a peak in the spring and summer. Ovulation is spontaneous. Females of some species experience a postpartum estrus and conceive their next litter while nursing the first, although the embryos do not implant until lactation ceases. Gestation lasts 20 to 40 days, and there are anywhere from one to nine young per litter, although litters of two to three are most common. The young are born blind and naked, and their eyes open between 11 and 21 days after birth. They nurse for three to four weeks. They often remain with their mother for a month after weaning. Females reach sexual maturity as young as 28 days, while males reach sexual maturity when they are at least 42 days old.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous ; delayed implantation ; post-partum estrous
Females build nests where they nurse their altricial young for three to four weeks. In some species, males assist females in caring for their offspring, grooming them, carrying them, and huddling with them. In fact, such male parental care has been shown to enhance survival of the young (Gubernick and Teferi 2000).
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Female, Protecting: Male, Female)
The Neotominae are a subfamily of the family Cricetidae. They consist of four tribes, 16 genera, and many species of New World rats and mice, predominantly found in North America. Among them are the well-known deer mice, white-footed mice, packrats, and grasshopper mice.
Neotomines are related to the other two subfamilies of mice in the New World, the Sigmodontinae and Tylomyinae. Many authorities place them all in a single subfamily, Sigmodontinae.
The Neotominae are a subfamily of the family Cricetidae. They consist of four tribes, 16 genera, and many species of New World rats and mice, predominantly found in North America. Among them are the well-known deer mice, white-footed mice, packrats, and grasshopper mice.
Neotomines are related to the other two subfamilies of mice in the New World, the Sigmodontinae and Tylomyinae. Many authorities place them all in a single subfamily, Sigmodontinae.
