Unit 1 [PDF] - Wisconsin Department of Natural Resources

Mustelids - members of the
weasel family including:
• weasels
• river otter
• fisher
• American marten
• badger
• mink
River Otter. FWS
Front
Rear
River Otter tracks.
Front and Rear
2.25” width by 2” length
Sets for River Otter:
• Slide or Trail Set
• Channel Set
• Toilet Set
Chapter 4 - Wisconsin’s Furbearer Resource
channels through vegetation are indications of muskrat activity. The small
“hand-like” prints of front feet, elongated hind feet, and a drag mark of its tail
between the tracks is distinctive. Their small brown pellet-like droppings are
about one-half inch long and often found in feeding areas and surrounding logs
or rocks protruding from the water.
Trapping Techniques:
Foot-hold traps for muskrat should be staked in deep water and the heavier
and more durable #1 ½ foot-holds should be used to make the set. The weight
of the trap is sufficient enough to submerge a muskrat so no slide wire and lock
is necessary in deep water. If there is too much vegetation that a trapped muskrat
may become entangled, or if the water is too shallow, then a guarded foothold
trap (stop-loss) or body-grip trap should be used. Colony traps or #110
body-grip or #150 can be used in muskrat runs (see current trapping regulations
for specific rules).
River Otter
Lontra canadensis; Order: Carnivora; Family: Mustelidae
Description:
Otter are large semi-aquatic members of the weasel family; they are long,
slender, short-haired furbearers known to be playful and intelligent. The fur is
a rich, glossy, shade of brown and lighter on the cheeks, throat and belly. Males
grow to 48 inches and 25 pounds while females are 4-6 inches shorter and
weigh 19 pounds or less. Both sexes have anal musk glands that release when
the animal is frightened. The musk is less pungent than other mustelids. Otters
have webbed toes, non-retractable claws and are excellent swimmers. They
have valves in their nose and ears that close when they are underwater.
Biology:
Adult otter begin mating at two years of age and may mate for life. After mating
in late spring or early summer, an average of 2-3 young are born the following
spring in April or May, following a period of delayed implantation. The
den may be an abandoned beaver lodge, bank hole, or hollow log. The young
stay with the parents until the next spring.
Otter are very adept at catching small fish and minnows, with rough fish
comprising most of the otter’s diet. Crayfish, frogs, turtles, muskrats, and small
reptiles are also eaten. Otter will repeated mark the same area with their scat as
a way to establish a territory. These areas are commonly referred to as “latrines”
or “toilets” and often occur at beaver dams.
Wisconsin Trapper Education Manual 28