Order Rodentia Family Geomyidae Diastema 1 pair incisors

Order Rodentia Family Geomyidae • • Diastema 1 pair incisors Ears shorter than tail External fur-lined pouches • Tail less than ¾ length of head, body • Hind feet smaller than forefeet Geomys bursarius

Order Rodentia Family Heteromyidae • • Diastema 1 pair incisors Ears shorter than tail External fur-lined pouches • Tail more than ¾ length of head, body • Hind feet larger than forefeet Perognathus flavescens

Perognathus flavescens Identification: Dorsum cinnamon with blackish hairs; venter lighter; lightcolored 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 38 annually Conservation: Endangered; several isolated populations

Order Rodentia Family Castoridae • • • Diastema 1 pair incisors Ears shorter than tail Hind feet webbed Tail scaly, paddleshaped Castor canadensis

Castor canadensis Common name: Beaver • Order Rodentia – Family Castoridae • Genus Castor – Species Castor canadensis http: //www. inhs. uiuc. edu/dnr/fur/species/beaver. html Presented by Catherine Luria

Castor canadensis Identification • Largest rodent in Iowa • TL 94 -120 cm; tail, 23 -37 cm; hind foot, 17 -19 cm; ear, 30 -35 mm • Usually weighs 15 -30 kg, up to 45 kg http: //www. inhs. uiuc. edu/dnr/fur/species/beaver. html

Castor canadensis Distribution • Much of North America from central Alaska and Northern Canada to Northern Mexico • Found throughout Iowa and north-central United States http: //www. huntington. edu/thornhill/images/wildlifephotos/beaver. jpg

Castor canadensis Habitat • Streams, rivers, marshes, and lakes • Often near willow, aspen, and other preferred food sources http: //www. huntington. edu/thornhill/images/wildlifephotos/beaver. jpg

Castor canadensis Diet • Summer: grasses, leaves, roots of aquatic plants, bark stripped from building materials, sometimes berries • Winter: leaves and inner bark of stored saplings and branches • Prefers willow, aspen, cottonwood, alder; tends to avoid pine except for building www. wildflorida. org/ critters/beaver. asp

Castor canadensis Diet • Stores food for winter by anchoring branches and saplings to bottom of pool • “Feed pile” is 3 -6 feet deep and up to 30 -40 feet wide • Beaver 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 Reproduction • Breeding starts in January of February • Female bears 1 -6 kits (usually 3 -4) in April, May, or June • Young are weaned in 6 weeks but will stay with family group 1 -2 years

Castor canadensis Reproduction • Family groups consist of around 12 beavers – One or more pairs of adults – Young of that year – Yearlings • Yearlings leave or • are driven off as • kits mature

Castor canadensis Conservation Status • Valuable pelt • Once trapped to extinction in some areas • Protective legislation and natural emigration have allowed beaver to reoccupy much of its former range • Now fairly common, even considered a pest in some areas http: //www. wildernessclassroom. com/w ww/schoolhouse/boreal_library/animals/ photos/beaver. jpg

Castor canadensis Disease • Can carry rabies • Carries tularemaia – Bacterial infection – Transmitted to humans through contact with beaver tissue or blood or through contaminated water – Causes headache, fever, chills, vomiting, aches and pains http: //www. wildernessclassroom. com/ww w/schoolhouse/boreal_library/animals/pho tos/beaver. jpg

Castor canadensis Dam building • Dams constructed of branches, rocks, leaves, and other debris and filled with mud from the stream bottom • 4 -7 feet across • Added to as water level rises • Smaller dams are sometimes constructed to relieve pressure on http: //www. exzooberance. com/virtual%20 zoo/they%20 s main dam wim/beaver/Beaver%20485050. jpg

Castor canadensis Why do beavers build dams? • Increases the depth and surface area of the stream or pond http: //www. bfro. net/avevid/nelson/images/beaver%20 dam. jpg – Easier to drag branches, etc. – Prevents the underwater entrance to the den or lodge from freezing over – Protects against predation – Allows greater access to food

Castor canadensis Beaver Lodges • Built against the back of the den or against the stream bank • Dome-like structure built of sticks and mud • Underwater entrance(s) http: //www. saskschools. ca/~gregory/animals/images/bvr 2. jpg

Castor canadensis Other • Primarily nocturnal/crepuscular • Presence easily detected by chewed saplings • Little predation: mink take young and large carnivores may attack adults

References Illinois 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/ian 601. 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.