Order RodentiaFamily GeomyidaeDiastema1 pair incisorsEars shorter than tailExternal fur-lined pouchesTail less than length of head, bodyHind feet smaller than forefeet

Geomys bursarius

Order RodentiaFamily HeteromyidaeDiastema1 pair incisorsEars shorter than tailExternal fur-lined pouchesTail more than length of head, bodyHind feet larger than forefeet

Perognathus flavescens

Perognathus flavescensIdentification: Dorsum cinnamon with blackish hairs; venter lighter; light-colored patch behind ears and around eyes

Distribution: West (Loess Hills), southeast, central Iowa

Habitat: Grassy slopes; well drained; small burrows

Perognathus flavescens

Diet: Seeds of grasses, other herbs

Reproduction: 2-3 litters of 3-8 annually

Conservation: Endangered; several isolated populations

Order RodentiaFamily CastoridaeDiastema1 pair incisorsEars shorter than tailHind feet webbedTail scaly, paddle-shaped

Castor canadensis

Castor canadensisCommon name: Beaver Order RodentiaFamily CastoridaeGenus CastorSpecies Castor canadensishttp://www.inhs.uiuc.edu/dnr/fur/species/beaver.htmlPresented by Catherine Luria

Identification Largest rodent in IowaTL 94-120 cm; tail, 23-37 cm; hind foot, 17-19 cm; ear, 30-35 mmUsually weighs 15-30 kg, up to 45 kghttp://www.inhs.uiuc.edu/dnr/fur/species/beaver.htmlCastor canadensis

DistributionMuch of North America from central Alaska and Northern Canada to Northern MexicoFound throughout Iowa and north-central United Stateshttp://www.huntington.edu/thornhill/images/wildlifephotos/beaver.jpgCastor canadensis

HabitatStreams, rivers, marshes, and lakesOften near willow, aspen, and other preferred food sourceshttp://www.huntington.edu/thornhill/images/wildlifephotos/beaver.jpgCastor canadensis

DietSummer: grasses, leaves, roots of aquatic plants, bark stripped from building materials, sometimes berriesWinter: leaves and inner bark of stored saplings and branchesPrefers willow, aspen, cottonwood, alder; tends to avoid pine except for buildingwww.wildflorida.org/ critters/beaver.asp

Castor canadensis

DietStores food for winter by anchoring branches and saplings to bottom of poolFeed pile is 3-6 feet deep and up to 30-40 feet wideBeaver leaves den through underwater entrance, gets food from the pile, and returns to the den www.occdsb.on.ca/ ~sel/rideau/beaver.htm

Castor canadensis

ReproductionBreeding starts in January of FebruaryFemale bears 1-6 kits (usually 3-4) in April, May, or JuneYoung are weaned in 6 weeks but will stay with family group 1-2 yearsCastor canadensis

ReproductionFamily groups consist of around 12 beaversOne or more pairs of adultsYoung of that yearYearlings Yearlings leave or are driven off as kits matureCastor canadensis

Conservation StatusValuable peltOnce trapped to extinction in some areasProtective legislation and natural emigration have allowed beaver to reoccupy much of its former rangeNow fairly common, even considered a pest in some areashttp://www.wildernessclassroom.com/www/schoolhouse/boreal_library/animals/photos/beaver.jpgCastor canadensis

DiseaseCan carry rabiesCarries tularemaiaBacterial infectionTransmitted to humans through contact with beaver tissue or blood or through contaminated waterCauses headache, fever, chills, vomiting, aches and painshttp://www.wildernessclassroom.com/www/schoolhouse/boreal_library/animals/photos/beaver.jpgCastor canadensis

Dam buildingDams constructed of branches, rocks, leaves, and other debris and filled with mud from the stream bottom4-7 feet acrossAdded to as water level risesSmaller dams are sometimes constructed to relieve pressure on main dam

http://www.exzooberance.com/virtual%20zoo/they%20swim/beaver/Beaver%20485050.jpgCastor canadensis

Why do beavers build dams?Increases the depth and surface area of the stream or pondEasier to drag branches, etc.Prevents the underwater entrance to the den or lodge from freezing overProtects against predationAllows greater access to foodhttp://www.bfro.net/avevid/nelson/images/beaver%20dam.jpgCastor canadensis

Beaver Lodges Built against the back of the den or against the stream bankDome-like structure built of sticks and mudUnderwater entrance(s)

http://www.saskschools.ca/~gregory/animals/images/bvr2.jpgCastor canadensis

OtherPrimarily nocturnal/crepuscularPresence easily detected by chewed saplingsLittle predation: mink take young and large carnivores may attack adults

Castor canadensis

ReferencesIllinois Department of Natural Resources. Ecology and Conservation of Illinois Fur Resources. http://www.inhs.uiuc.edu/dnr/fur/index.html

Iowa Association of Naturalists. Iowa Mammals. http://www.extension.iastate.edu/publications/ian601.pdf

Jones, J. Knox, Jr. and Elmer C. Birney. 1988. Handbook of Mammals of the North-Central States. University of Minnesota Press, Minneapolis.

Kays, Roland W. and Don E. Wilson. 2002. Mammals of North America. Princeton University Press, Princeton, NJ.