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IDENTIFICATION of MUSKRAT

IDENTIFICATION of MUSKRAT. KINGDOM: Animalia PHYLUM: Chordata CLASS: Mammalia ORDER: Rodentia FAMILY: Muridae GENUS: Ondatra SPECIES: Zibethicus. IDENTIFICATION (cont.) Total length: 545-640mm (21-25”) Tail length: 250-283mm (9-11”)

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IDENTIFICATION of MUSKRAT

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  1. IDENTIFICATIONofMUSKRAT KINGDOM: Animalia PHYLUM: Chordata CLASS: Mammalia ORDER: Rodentia FAMILY: Muridae GENUS: Ondatra SPECIES: Zibethicus

  2. IDENTIFICATION (cont.) Total length: 545-640mm (21-25”) Tail length: 250-283mm (9-11”) Hind foot length: 65-78mm (2.5-3”) Ear length: 20-21mm (~1”) Weight: 700-1800g (1.3-4 lbs.) Neonates: ~ 21g

  3. IDENTIFICATION (cont.) • Generally, dark brown • Fur color can vary from white & silver through tan, reddish-brown, and black • Ventral pelage lighter than the rest of the fur • Tail and feet are usually dark brown or black

  4. IDENTIFICATION (cont.) • Total of 16 teeth • Incisors: 1 pair • Canines: 0 • Premolars: 0 • Molars: 3 on each side • Dental formula: I-1/1, C-0/0, P-0/0, M-3/3=16

  5. TAIL Flattened and scaly EYES Top of the head allowing it to see above water while swimming.

  6. TRACKS and SCAT

  7. BIOLOGY Scent glands: two at the base of the tail (hence the name muskrat) Tail: scaly, flattened, serves as a rudder when swimming Feet: partly webbed hind feet, with short stiff hairs lining the toes, called the ‘swimming fringe’ Swimming: can swim at a rate of 1.5-5km/hr, can swim backwards, & can stay submerged for up to 20 minutes

  8. BIOLOGY (cont.) Pelage: layer of soft, dense underfur interspersed with long, coarse guard hairs. The underfur is waterproof, and a layer of trapped air in the non-wettable fur enhances the buoyancy and insulation. Annual molt: begins in the summer, minimum density in August

  9. BODY TEMPERATURE Tail: helps with thermoregulation by functioning as a heat sink Wika & Pasche: heat loss through the tail is proportional to the temperature gradients between the tail and the environment Prevent loss of body heat: -get out of the water -increase abdominal temp.

  10. LIFE HISTORY • Generally promiscuous • Males compete fiercely for mates • Sexually active spring after birth • Spermatogenesis begins in early spring and lasts into late autumn • Vaginal orifice is sealed from birth and opens just before breeding activity • Estrus cycle: 3-6 days • Gestation period: 25-30 days • Litter size: 4-8 (mean of 6 or 7)

  11. LIFE HISTORY (cont.) Litter size and number influenced by: -latitude -southern latitudes: more litters/year -habitat quality -poorer habitat produce fewer litters and smaller sizes

  12. LIFE HISTORY (cont.) • NEONATES: • Blind • Hairless • Pink or gray in color • Rounded tail

  13. LIFE HISTORY (cont.) • YOUNG: • Covered with soft fur • Swim within 14 days • Tail becomes compressed during 2nd month • Weaned at 4 weeks • Males grow faster than females • Average life is only 2-3 years

  14. ECOLOGY FEEDING: Omnivorous PREY: amphibians, snails, crustaceans, mussels, turtles, fish, roots and leaves of hydrophytes

  15. ECOLOGY (cont.) • PREDATORS: • Raccoons • Red foxes • Wild dogs • Bald eagles • Great-horned owl • Red-tailed hawk • Hunters/trappers

  16. ECOLOGY (cont.) • HOUSING LOCATIONS: • Conical houses • Dig burrows into banks • Push-ups over icecracks TYPES OF HOUSES: • Main dwelling house • Feeding house

  17. HOUSING DESIGN/ARCHITECTURE: • Site selection influenced by: water depth, soil texture, amount of aquatic vegetation • Begin building in May/June, October • Large lodges of vegetation—will live in small family groups • Multiple lodges in an area—up to 5 muskrats/lodge • Construction begins on firm substrate, w/dominant emergent vegetation • Houses built above the water level • Several underwater tunnels • Nest chambers lined with fresh plant material

  18. HOUSING(cont.) • Temperature inside houses higher than surrounding temperature • “Huddling”-increases the temperature, increasing survival during the winter

  19. HOME RANGE: • Small home range • Within 15 m of their primary dwelling • Foraging usually within 5-10 m of lodge or push-up • Move greater distance on rainy days

  20. DISPERSAL: • Occurs in March/April • Dispersal initiated by: • Snow • Ice • Air temperature • Population density • Sex/age composition • Forced movements caused by floods, drought, intraspecific strife

  21. DISPERSAL (cont.): • After dispersal, usually return to their home range • Study by Mallach: • 500-2,000 m away-----57% returned • 3,000 m away----------31% returned • 4,000 m away----------15% returned

  22. DISEASES: -Adiaspiromycosis -Ringworm disease -Epizootic disease -Salmonellosis -Hemorrhagic disease -Tuluremia -Leptospirosis -Tyzzer’s disease -Pseudotuberculosis -Yellow fat disease

  23. PARASITES: -36 trematodes -19 nematodes -13 cestodes - 2 acanthocephalans -17 acarina

  24. ENDOPARASITES: -Trematodes: -Echinostoma revolutum -Plagiorchis proximus -Quinqueserialis quinqueserialis -Nematodes: Trichuris opaca -Cestodes: -Hymenolepsis spp. -Taenia taeniaeformis *little impact, except Taenia taeniaeformis (tapeworm)- causes females to produce fewer young

  25. ECTOPARASITES: -mites -ticks *can cause skin rash, but generally not fatal

  26. POPULATION STATUS • Solid population throughout N. Am., as well as in KY. • Occur from the Yukon & NW Territories to the Gulf of Mexico, and from the Aleutian Islands east to the Atlantic coast, and south to N. Carolina

  27. POPULATION (cont.) • Muskrat population generally follow a 10 year cycle. • An increase in muskrat population is often followed by an increase in mink population a year later, and an increase in mink population is generally followed by a decrease in muskrats a year later. • Populationis estimated based on the fur harvest. • Muskrat houses can be used to estimated population densities. • They are not threatened or endangered.

  28. WETLAND HABITAT NEEDS • Fresh and Saltwater marshes, swamps, river banks, ponds, lakes • Nest in bulky nests of plants on open swampland • Also nest in tunnels dug into river banks above the high water mark

  29. WETLAND HABITAT NEEDS(cont.) • Require aquatic vegetation for food and for housing material • Food such as snails, crustaceans, mussels, turtles, fish

  30. MANAGEMENT CONCERNS • The most valuable semi-aquatic furbearing mammal, with the pelt industry in the millions of dollars RUSSIAN HAT BOMBER HAT

  31. MANAGEMENT CONCERNS (cont.) • Mgmt. Practices to increase muskrats: • Create marshes, ponds • Don’t destroy wetlands for agriculture • Control water levels on marshes with an irregular water source to encourage growth of favored plant species • Construct level ditches in shallow marshes to ensure adequate water depths during winter • Controlled burning during early spring to prevent buildup of dead vegetation and release nutrients into the ecosystem • Fence off all except a small portion of ponds, creeks, and wetlands on farms where livestock are kept to prevent grazing and trampling of the shoreline

  32. MANAGEMENT CONCERNS (CONT.) • PROBLEMS: • Garden damage • Overgraze marsh vegetation • Burrow holes under dams and dikes • Cause damage to irrigation canals & farm ponds • “Eat-outs”-the extensive loss of vegetation & resulting silting that makes the areas less productive for other species of wildlife

  33. MANAGEMENT CONCERNS (cont.) • OVERPOPULATION REMEDIES • Treat garden plants with ROPEL • Gassing/poisoning • Shooting/trapping • Water drawdowns or burning • “Rip-rap” banks with crushed stone

  34. MANAGEMENT CONCERNS (cont.) • KY HUNTING/TRAPPING REGULATIONS • All furbearer hunting/trapping: • Raccoon, opossum, mink, muskrat, beaver, red fox, gray fox, weasel, striped skunk • Noon 11/10/03 - noon 2/29/04 • no hunting or trapping bag limits

  35. IDENTIFICATION OF NUTRIA Order: Rodentia Family: Myocastoridae Genus: Myocastor Species: Coypus

  36. DESCRIPTION • SIZE • Head and body: 22-25” • Tail: 12-17” • Weight: 10-30 lbs

  37. DESCRIPTION (cont.) • Pelage: soft dense underfur and long, coarse guard hairs. Underfur is densest on the abdomen and thickest during the winter. • Pelage color: yellow-brown to dark-brown, with the chin covered by white hairs. The tail is scantily haired. • Long, round tail

  38. DESCRIPTION (cont.) • FEET • First 4 digits of the hind feet are webbed • 5th toe is free and used in grooming • Front digits are strongly clawed • Pollex is reduced • Soles of the feet are hairless

  39. BIOLOGY • Female has 4 or 5 pairs of mammary glands located dorsally, which allows for suckling young while swimming • An oily secretion from glands located at the base of sensory bristles near the mouth and anus lubricates the pelage when grooming • These secretions are also used to delineate home ranges

  40. BIOLOGY (cont.) • Femurhas a well developed trochanter for attachment of the muscles involved in swimming • Well developed deltoid crest and a large scapula fossa aid in burrowing • Nocturnal, and spend most of their time feeding, grooming, and swimming • Become diurnal during cold periods to recover feeding time lost while huddling at night • Can remain submerged for greater than 10 minutes

  41. LIFE HISTORY • REPRODUCTION • Nonseasonal breeders • Peak births- Jan., Mar., May, Oct. in Oregon • Peak births- Dec.-Jan. and June-July in Louisiana • Mean litter size: 3-6 (declines during winter months & increases when food is abundant and mild winter) • Usually have litters in open nests at the edge of a body of water, or in large nest chambers deep in their burrows • ~27% of litters are aborted

  42. REPRODUCTION (cont.) • Young are precocial • ~225g at birth • Rapidly gain weight during first 5 months • No difference in mass between males and females at birth, but when fully grown males are up to 15% heavier

  43. ECOLOGY • Live in aquatic habitats- rivers, lakes, ponds, marshes, bogs • Swims well, makes shallow burrows in banks with an enlarged nesting chamber at rear • Remain in one area throughout their life, however freezing weather or drought may cause migration • Daily cruising range is less than 45 m • Daytime activity is influenced by temperature, with sunning and sleeping being the main activities if less than 28ºC

  44. POPULATION STATUS • Native to South America • As a result of escapes and liberations from fur farms, populations now exist around the world • By 1959, there were 20 million in Louisiana • First pelts reached the market in 1944, and harvest grew to 1 million pelts by 1987

  45. WETLAND HABITAT NEEDS • Prefer river banks, marshes, ponds, swamps, bogs • Like to burrow in banks • Aquatic vegetation for food – stems, leaves, roots, and bark (also feed on agricultural crops)

  46. MANAGEMENT CONCERNS • Not generally a problem, except at high densities • Disrupt drainage systems, damage crops, disturb natural plant communities • Burrows can weaken river banks that keep low lying land from flooding • CONTROL PROCEDURES • Shooting, trapping, baiting, chemicals

  47. MANAGEMENT CONCERNS (cont.) • Severe cold weather can decrease pop. • S. Am. Predators-jaguar, mountain lion, little spotted cat, caymans • La. Predators-alligators, gars, turtles, large snakes

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