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big-eared woodrat

Neotoma macrotis

What do they look like?

The fur of big-eared woodrats can range from light to dark brown with shades of gray. This species can be told apart from other woodrat species based on the size and shape of their skull. In general, females are 183.9 mm long and males are 193.8 mm long. Big-eared woodrats weigh an average of 204 g. Infant woodrats lack hair when they are born, although they do already have their whiskers. Healthy pups weigh 12 to 14 grams. Their backs start to darken after a couple days, with hair starting to grow after a couple weeks. The pups control their movements before they can open their eyes, which happens about 13 to 14 days after being born. (Haley, et al., 2007; Matocq and Murphy, 2007; Matocq, 2002; Wood, 1935)

  • Sexual Dimorphism
  • male larger
  • Range mass
    190.4 to 217.6 g
    6.71 to 7.67 oz
  • Range length
    181.1 to 196.9 mm
    7.13 to 7.75 in
  • Average length
    188.1 mm
    7.41 in

Where do they live?

Big-eared woodrats (Neotoma macrotis) are found from parts of California into Mexico. They are found as far north as Salinas Valley in California and as far south as Baja California, Mexico. They are also in most parts of southern California between these two points, as well as in the southern part of the Sierra Nevada and the Coastal Mountain Range. (Haynie, et al., 2007; Matocq and Murphy, 2007)

What kind of habitat do they need?

Big-eared woodrats are found in large numbers in areas densely populated with trees, specifically coast live oaks and California foothill pines. Although they are more common in wooded areas, they are also found along rivers. These woodrats are also found in shrublands and coastal areas of California and Baja California. They are also more common in areas with understory plants including Pacific poison oaks, toyons, and California buckthorns. There are no specified altitude ranges for this species; however, big-eared woodrats live in and around the Sierra Nevada mountain range, although they are found mainly in the foothills. (Haynie, et al., 2007; Matocq and Murphy, 2007; Skopec, et al., 2008)

  • These animals are found in the following types of habitat
  • temperate

How do they reproduce?

Big-eared woodrats have many mating rituals. This involves sniffing by both and presentation by the female. This species can be very aggressive. Breeding pairs in the lab often have fights, which may result in injuries or death. This also happens in the wild. Both male and female woodrats show their interest by circling, sniffing, and licking their potential mates. Signs of fighting can occur, with the woodrats standing on their hind limbs and leaning against one another supported by their forelimbs. If these behaviors are successful, the female stays still and raises her hind end. Males may mate up to eight times in a ten minute period, each mating attempt takes an average of five seconds. When males are done mating, they leave the female. In captivity, this species has low fertility rates and does not breed well. Males tend to mate successfully with more than one female. (Haynie, et al., 2007; Matocq and Lacey, 2003; Matocq, 2004; Wood, 1935)

The breeding season of big-eared woodrats is February to September, even though they sometimes breed outside of these months. Young woodrats in their first mating season may appear mature; however, they often fail to reproduce successfully, which likely means that there are additional factors that determine whether they are ready to mate. Female big-eared woodrats are pregnant for an average of 33 days before having up to 3 young. At this time, the female's four mammae start to swell and lactate. (Matocq and Lacey, 2003; Matocq, 2004)

  • How often does reproduction occur?
    Male big-eared woodrats can breed multiple times throughout the breeding season, while females generally only breed about 3 times within the same time span.
  • Breeding season
    Big-eared woodrats breed from February to September.
  • Range number of offspring
    2 to 3
  • Average gestation period
    33 days

Mothers tend to provide more care for their offspring than the fathers. This care includes providing milk to their young. Although in many cases, mother simply ignore, choose to abandon, and even eat their offspring. Mothers who give birth in captivity are somewhat protective of their young; they are feisty when their offspring are approached and they relocate their offspring by biting them on their neck or shoulder to move them to a safer location. Fathers show varying patterns of parental investment, some stay and help the mother in rearing their offspring. (Wood, 1935)

How long do they live?

There is currently very little information available regarding the lifespan of big-eared woodrats. One current estimate suggests that these woodrats have an approximate lifespan of about 1.6 years. However, other species from this genus have a much longer estimated lifespan. For instance, white-throated woodrats have an estimated captive lifespan of 9.5 years, eastern woodrats have an estimated captive lifespan of 8.6 years, and desert woodrats have an estimated captive lifespan of 10.5 years. (Matocq, 2004; Tacutu, et al., 2013)

How do they behave?

Big-eared woodrats are active at night. These woodrats build "houses" or dens from left over shrubs, sticks, and plant material. Hollow logs can serve as alternate houses/dens. Dens likely play a role in forming kinship among females. Male behavior may vary more. Males stick around for any given amount of time, before and after mating, and are not as strongly associated to any one house as females are, although they often help build them. Dens may help establish territory, where only certain, related big-eared woodrats are allowed to enter. Some dens may have survived for as long as 60 years and may be "passed" down to female offspring. Just under a quarter of all neighboring houses were inhabited by closely related species and just over half return and live either in the house where their mother lived or in a neighboring one. (Matocq and Lacey, 2003; Wood, 1935)

  • Range territory size
    159.8 to 204.0 m^2

Home Range

Females consistently return to their dens after being captured and released and spend the majority of their time within 100 m of their dens. Their average home range is about 181.9 m^2 ± 22.1, with houses every 7.5 m ± 0.6. (Matocq and Lacey, 2003)

How do they communicate with each other?

Large-eared woodrats use their visual perception to navigate in the environment and to stay at a safe distance from other animals. Their breeding behaviors involve close proximity and contact, either aggressive or non-aggressive. While going through heat, females release pheromones that excite males in the area. Related female big-eared woodrats might also be at an advantage due to their cooperation and effective communication. (Matocq and Lacey, 2003; Wood, 1935)

What do they eat?

More than 80% of the diet of big-eared woodrats is composed of tree bark and leaves from coast live oaks. Due to the chemical makeup of these trees, digesting this material is not easy. However, big-eared woodrats have an adapted metabolism that allows them to break down these compounds. When big-eared woodrats are in an area that overlaps with one of their sister species, such as dusky-footed woodrats or desert woodrats, they continue to eat what they usually do, while the sister species changes their eating habits to accommodate them, even though all of the species mostly eat oak leaves. This show how specialized their diet is and that they are better competitors than the other species. (Haley, et al., 2007; Matocq and Murphy, 2007; Matocq, 2004; Skopec, et al., 2008)

  • Plant Foods
  • leaves
  • wood, bark, or stems

What eats them and how do they avoid being eaten?

Predators of big-eared woodrats include northern spotted owls, as well as local snake species and birds of prey. To get away from birds of prey, big-eared woodrats hide in their dens. (Haynie, et al., 2007)

What roles do they have in the ecosystem?

Big-eared woodrats carry several human pathogens. In addition, northern spotted owls are considered an endangered species and one of their main prey items are big-eared woodrats. Thus destruction of big-eared woodrats' habitat could lead to an even greater decline in the owl's numbers, or potentially to their extinction. (Haynie, et al., 2007)

Commensal or parasitic species (or larger taxonomic groups) that use this species as a host
  • Borrelia burgdorferi
  • Ehrlichia phagocytophila
  • Yersinia pestis

Do they cause problems?

Big-eared woodrats are known hosts and transporters of viruses that infect humans. (Haynie, et al., 2007)

  • Ways that these animals might be a problem for humans
  • injures humans
    • carries human disease

How do they interact with us?

There are no documented ways in which big-eared woodrats benefit humans economically.

Are they endangered?

Though the species is not endangered, there is concern over habitat destruction, especially in shrubby areas due to human developments such as mining and agriculture. (Skopec, et al., 2008)

Some more information...

Contributors

Tim Saltys (author), Indiana University-Purdue University Fort Wayne, Mark Jordan (editor), Indiana University-Purdue University Fort Wayne, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

References

Haley, S., J. Lamb, M. Franklin, J. Constance, M. Dearing. 2007. Xenobiotic Metabolism of Plant Secondary Compounds in Oak (Quercus agrifolia) by Specialist and Generalist Woodrat Herbivores, Genus Neotoma. Journal of Chemical Ecology, 33/11: 2111-2122.

Haynie, M., C. Fulhorst, M. Rood, S. Bennett, B. Hess, R. Bradley. 2007. Genetic Variation in Multilocus Microsatellite Genotypes in Two Species of Woodrats (Neotoma macrotis and N. fuscipes) from California. Journal of Mammalogy, 88/3: 745-758.

Matocq, M. 2002. Morphological and Molecular Analysis of a Contact Zone in the Neotoma fuscipes Species Complex. Journal of Mammalogy, 83/3: 866-883.

Matocq, M. 2004. Reproductive Success and Effective Population Size in Woodrats (Neotoma macrotis). Molecular Ecology, 13/6: 1635-1642.

Matocq, M., E. Lacey. 2003. Philopatry, Kin Clusters, and Genetic Relatedness in a Population of Woodrats (Neotoma macrotis). Behavioral Ecology, 15/4: 647-653.

Matocq, M., P. Murphy. 2007. Fine-Scale Phenotypic Change Across a Species Transition Zone in the Genus Neotoma: Disentangling Independent Evolution from Phylogenetic History. Evolution, 61/11: 2544-2557.

Skopec, M., S. Haley, A. Torregrossa, M. Dearing. 2008. An Oak (Quercus agrifolia) Specialist (Neotoma macrotis) and a Sympatric Generalist (Neotoma lepida) Show Similar Intakes and Digestibilities of Oak. Physiological and Biochemical Zoology, 81/4: 426-433.

Tacutu, R., T. Craig, A. Budovsky, D. Wuttke, G. Lehmann, D. Taranukha, J. Costa, V. Fraifeld, J. de Magalhaes. 2013. Human Ageing Genomic Resources: Integrated databases and tools for the biology and genetics of ageing. Nucleic Acids Research, 41(D1): D1027-D1033. Accessed July 30, 2014 at http://genomics.senescence.info/species/browser.php?type=5&name=Neotoma.

Wood, F. 1935. Notes on the Breeding Behavior and Fertility of Neotoma fuscipes macrotis in Captivity. Journal of Mammalogy, 16/2: 105-109.

 
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Saltys, T. 2014. "Neotoma macrotis" (On-line), Animal Diversity Web. Accessed November 22, 2017 at http://www.biokids.umich.edu/accounts/Neotoma_macrotis/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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