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Neotoma anthonyiAnthony's woodrat

By Hailey Jenks

Geographic Range

Anthony's woodrats (Neotoma anthonyi) are native to two islands: Todos Los Santos Islands, along the peninsula of Baja California, Mexico. They are now considered extinct due to predation by domestic or feral cats (Felis domesticus). (Álvarez-Castañeda and Castro-Arellano, 2018; Nowak, 1999)

Habitat

The northern Todos Los Santos Island is mostly flat and rocky, and the highest elevation is 45 m. The southern island is mostly low plateau with steep cliffs at the shorelines, with the highest elevation reaching 95 m (Cortés-Calva et al., 2001). Anthony's woodrats are entirely terrestrial mammals. Coastal scrub is the main vegetation type found on the Todos Los Santos Islands.

Like other woodrats, Anthony’s woodrats are thought to use rocky outcrops and rocky crevices to create middens (mostly contain feces and other materials, such as plants). Research has found evidence of old middens located in shallow caves less than a meter deep on the islands (Mellink, 1992). (Álvarez-Castañeda and Castro-Arellano, 2018; Cortés-Calva, et al., 2001; Mellink, 1992)

  • Range elevation
    95 (high) m
    311.68 (high) ft

Physical Description

Anthony's woodrats have greyish-brown pelage, with their hind legs, tails and dorsal being darker compared to the rest of their bodies. Their ventral sides are dull white.

Allen (1898) reported that females are 3% smaller in length than males. Males average 320.6 mm in total body length, while females measure approximately 316.8 mm. Their tail lengths range from 132 to 146 mm. Their hind feet are, on average, 34 to 36 mm long. Their ears measure approximately 24 mm. Anthony's woodrats have a total of 16 teeth, with a dental formula of 1003/1003.

Males weigh 180.2 to 260.8 g, while females weigh 142.4 to 197.2 g.

Anthony's woodrats have a total skull size of approximately 46 mm and a basal breadth of 42 mm. The greatest reported width across their zygomata (the bony arch of the cheeks, formed by the zygomatic and temporal bones) was 25 mm. Both males and females have rounded nasals. Anthony's woodrats have larger skulls compared to other members of the genus Neotoma (Cortes-Calva et al. 2001).

There are no reports of seasonal variation in pelage color. Juveniles are darker than adults, but there are no published measurements for juveniles. (Allen, 1898; Cortés-Calva, et al., 2001)

  • Sexual Dimorphism
  • male larger
  • Range mass
    142.4 to 260.8 g
    5.02 to 9.19 oz
  • Range length
    316.8 to 320.6 mm
    12.47 to 12.62 in

Reproduction

Little is known about the mating systems of Anthony's woodrats. Shurfliff et al. (2014) examined the mating habits of two similar species: Bryant's woodrats (Neotoma bryanti, formerly considered the same species as Anthony’s woodrats) and desert woodrats (Neotoma lepida). Two main factors in amte selection in these species mate selection was aggression and size. This study concluded that larger females are more likely to mate with smaller males, while smaller females are less likely to mate with larger males (Shurtliff et al., 2014). Further, Shurtliff (2009) reported that desert woodrats are polyandrous, meaning females mate with multiple males. It is likely that Anthony's woodrats have a similar mating system. (Shurtliff, 2009; Shurtliff, et al., 2014)

No reproductive information has been reported for Anthony’s woodrats. Therefore, all information here refers to close relatives in the genus Neotoma. In closely-related desert woodrats (Neotoma lepida), the breeding season occurs from October to May. Their gestation period is typically 30 to 36 days, with an average litter size of 2.7. Time to weaning in desert woodrats is 27 to 40 days. Desert woodrats breeding once per yearFemales reach sexual maturity after two to three months. It is expected that Anthony's woodrats have similar reproductive behaviors. ("California Wildlife Habitat Relationships System: Desert woodrat", 2008)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • viviparous

There has been no research on parental investment in Anthony's woodrats. Shurtliff (2009) studied parental investment in both Bryant's woodrats (Neotoma bryanti) and desert woodrats (Neotoma lepida). This research reported that these Neotoma species display parental investment in their offspring. Out of 169 desert and Bryant's woodrat offspring captured, 43% of juveniles had both parents present, 32% had one parent present, and 4% had parents that were not present. Shurtliff (2009) also reported that mothers tend to stay closer to juveniles that are under 95 g. (Shurtliff, 2009)

Lifespan/Longevity

Little is known about the lifespan of Anthony's woodrats. According to Gorbunova et al. (2008), desert woodrats (Neotoma lepida) can live upwards of 10 years in the wild. It is likely Anthony's woodrats have a similar lifespan in the wild.

Anthony's woodrats are not kept in captivity. Closely related species, desert woodrats and Bryant's woodrats (Neotoma bryanti), have been kept in captivity to determine their preference in mate choice (Shurtliff, 2009). However, the lifespan of these woodrats in captivity was not mentioned. (Gorbunova, et al., 2008; Shurtliff, 2009)

Behavior

Not much is known about the behaviors of Anthony's woodrats, but much is known about others in the genus Neotoma. In general, woodrats are solitary and very territorial. Many woodrats will build nests with materials including sticks and rocks as a means of protection from prey, as well as for rearing young. Woodrats are also fossorial, meaning they live at least partly underground.

Female woodrats can be aggressive towards males while choosing mates. This aggression has been documented in female Bryant's woodrats (Neotoma bryanti), which are sympatric with Anthony's woodrats. Further, larger female Bryant’s woodrats will mate with smaller males, but smaller females will not mate with larger males. Males are known to alter home ranges to look for mates.

In general, woodrats use echolocation to communicate and choose mates. They can also detect traces of urine and feces left by conspecifics.

It is possible that the behaviors described above are similar in Anthony’s woodrats. (August, 1978; "California Wildlife Habitat Relationships System: Desert woodrat", 2008; Shurtliff, et al., 2014; White and Fleming, 1897)

Home Range

Home range and territory have not been reported for Anthony’s woodrats. In closely-related Bryant's woodrats (Neotoma bryanti), males are known to alter their home ranges to look for mates. Eastern woodrats (Neotoma floridana) have reported home ranges of 0.26 ha in adult males. Female eastern woodrats have smaller home ranges, averaging 0.17 ha. It is likely that Anthony's woodrats have similar home ranges. (Shurtliff, 2009; Tomlinson, 2008)

Communication and Perception

Little is known about communication and perception in Anthony’s woodrats. However, much is known about other members of the genus, Neotoma. Woodrats can use chemical and audio perception as forms of communication. They use urine and feces to communicate with other members of the species. Both male and female woodrats react very strongly to odors left behind by others. They also echolocate and create sounds while mating or competing for resources. Males use vocalization to attract females. (August, 1978; White and Fleming, 1897)

Food Habits

Anthony's woodrats are herbivores, and are considered to be generalist foragers on their islands. It is suspected that they predominately eat greens, such as leaves and fresh fruits.

Closely-related desert woodrats (Neotoma lepida), when residing in regions containing coastal scrub, consume a variety of plant and tree matter. A common behavior in the genus Neotoma is storing food for later consumption. It can be assumed that Anthony's woodrats forage similarly. ("California Wildlife Habitat Relationships System: Desert woodrat", 2008; Goldman, 1910; Torregrossa and Dearing, 2009)

  • Plant Foods
  • leaves
  • roots and tubers
  • wood, bark, or stems
  • seeds, grains, and nuts

Predation

Anthony's woodrats are preyed upon by feral cats (Felis catus). Allen (1898) suggests that their extinction was due to their inability to outrun these novel predators. (Allen, 1898)

Ecosystem Roles

Anthonys' woodrats have no reported ecosystem roles, but they act as herbivores on their islands. Many of the plants woodrats consume contain toxins. Some woodrats store their food for later consumption as a means to reduce the toxins through a process called volatilization. Torregrossa and Dearing (2009) reported that closely-related Bryant's woodrats (Neotoma bryanti) and desert woodrats (Neotoma lepida) rarely stored their food to detoxify it.

The only known predators of Anthony's woodrats are domestic or feral cats (Felis catus) which presumably caused their extinction.

Rangel et al. (2012) reported that sticktight fleas (Echidnophaga gallinacea) were found on Bryant’s woodrats. It is likely that Anthony’s woodrats host similar flea ectoparasites. (Torregrossa and Dearing, 2009; Allen, 1898; Goldman, 1910; Rangel, et al., 2012; Torregrossa and Dearing, 2009)

Economic Importance for Humans: Positive

It is not known if Anthony's woodrats have any positive economic impacts on humans.

Economic Importance for Humans: Negative

It is not known if Anthony's woodrats have any negative economic impacts on humans.

Conservation Status

Anthony's woodrats are listed as an "Extinct" species on the IUCN Red List. No special status is given to them on the United States Endangered Species Act list, in the CITES appendices, or on the State of Michigan List.

Anthony's woodrats are presumed extinct due to predation by domestic and feral cats (Felis catus). Although there were surveying efforts to find these woodrats three decades ago (1988-1990), none have been found (Cortez-Calva et al. 2001). Therefore, there are no conservation measures in place. (Allen, 1898; Cortés-Calva, et al., 2001)

Contributors

Hailey Jenks (author), Radford University, Lauren Burroughs (editor), Radford University, Logan Platt (editor), Radford University, Karen Powers (editor), Radford University, Galen Burrell (editor), Special Projects.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

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.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

echolocation

The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.

endothermic

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

folivore

an animal that mainly eats leaves.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

island endemic

animals that live only on an island or set of islands.

male parental care

parental care is carried out by males

motile

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.

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

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

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

visual

uses sight to communicate

viviparous

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

References

California Interagency Wildlife Task Group, California Department of Fish and Game. California Wildlife Habitat Relationships System: Desert woodrat. M126. Sacramento, California: California Department of Fish and Game. 2008. Accessed April 27, 2020 at https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=2521.

Allen, J. 1898. Descriptions of New Mammals from Western Mexico and Lower California. New York, New York: American Museum of Natural History.

Arnaud, G., A. Rodriguez-Moreno, A. Cordero-Tapia, S. Sandoval. 2016. Parasitism of Cuterebra (Diptera: Oestridae) on rodents of islands of the Gulf of California, Mexico. Journal of Parasitology and Vector Biology, 8/9: 92-98.

August, P. 1978. Scent communication in the southern plains wood rat, Neotoma micropus. The American Midland Naturalist, 99/1: 1-13.

Cortés-Calva, P., S. Ticul Alvarez-Castañeda, E. Yensen. 2001. Neotoma anthonyi. Mammalian Species, 663: 1-3.

Distel, R., J. Villalba. 2018. Use of unplayable forages by ruminants: The influence of experience with the biophysical and social environment. Animals, 8/4: 56. Accessed February 04, 2020 at https://doi.org/10.3390/ani8040056.

Goldman, E. 1910. North American Fauna #31: Revision of the Wood Rats of the Genus Neotoma. Washington D.C.: U.S. Fish and Wildlife Service.

Gorbunova, V., M. Bozzella, A. Seluanov. 2008. Rodents for comparative aging studies: From mice to beavers. Age (Dordr), 30/2-3: 111-119. Accessed March 16, 2020 at doi: 10.1007/s11357-008-9053-4. Epub 2008 Jun 25..

Hornsby, A., M. Matocq. 2016. Demographic and Phenotypic Reactions to Climate by Western North American Woodrats (Neotoma spp.) (Ph.D. Dissertation). Reno, Nevada: University of Nevada.

Kohl, K., D. Dearing. 2012. Experience matters: Prior exposure to plant toxins enhances diversity of gut microbes in herbivores. Ecology Letters, 15/9: 1008-1015.

Kohl, K., R. Weiss, C. Dale, D. Dearing. 2011. Diversity and novelty of the gut microbial community of an herbivorous rodent (Neotoma bryanti). Symbiosis, 54/9: 47-54.

Mellink, E. 1992. The status of Neotoma anthonyi (Rodentia, Muridae, Cricetinae) of Todos Santos Islands, Baja California. Mexico. Bulletin, 91/3: 137-140.

Nowak, R. 1999. Walker's Mammals of the World, 6th Edition: Volume 1. Baltimore, Maryland: The Johns Hopkins University Press.

Rangel, D., M. Pecolar, C. Fogarty, J. Campbell, L. Kreuger, T. Morgan, R. Cummings. 2012. The development and use of a duplex real-time PCR for the detection of Rickettsia typhi and Rickettsia felis in fleas collected in Orange and Los Angeles Counties, California. FEMS Immunology and Medical Microbiology, 87/1: 221-225.

Shurtliff, Q., P. Murphy, M. Matocq. 2013. Ecological segregation in a small mammal hybrid zone: Habitat-specific mating opportunities and selection against hybrids restrict gene flow on a fine spatial scale. International Journal of Organic Evolution, 68/3: 729-742.

Shurtliff, Q. 2009. Genetic, Behavioral, and Ecological Dynamics of a Woodrat Hybrid Zone (Genus Neotoma) in Southern California (Ph.D. Dissertation). Pocatello, Idaho: Idaho State University.

Shurtliff, Q., P. Murphy, J. Yeites, M. Matocq. 2014. Experimental evidence for asymmetric mate preference and aggression: Behavioral interactions in a woodrat (Neotoma) hybrid zone. BMC Evolutionary Biology, 220: 1-13.

Ticus, S., P. Alvarez-Castaneda, E. Yensen. 1999. Neotoma bryanti. Mammalian Species, 619: 1-3.

Tomlinson, W. 2008. Eastern woodrat (Neotoma floridana). Mammals of Mississippi, 8: 1-8. Accessed April 29, 2020 at https://www.cfr.msstate.edu/wildlife/mammals/pdf/Easternwoodrat.pdf.

Torregrossa, A., M. Dearing. 2009. Caching as a behavioral mechanism to reduce toxin intake. Journal of Mammalogy, 90/4: 807.

White, N., A. Fleming. 1897. Auditory regulation of woodrat (Neotoma lepida) sexual behaviour. Animal Behaviour, 35/5: 1281-1297.

Álvarez-Castañeda, S., I. Castro-Arellano. 2018. "Neotoma bryanti ssp. anthonyi" (On-line). The IUCN Red List of Threatened Species 2018 e.T14576A124171511. Accessed February 04, 2020 at https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T14576A124171511.en.

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