Watershed Facts / Mammals

Mammals in the Streams of the Harpeth River Watershed

The Harpeth River and its tributaries are home to many mammal species. Mammals associated with the Harpeth River are very dependent on riparian zones. The riparian zone, the land area adjacent to streams, is the critical interface between land and water. Riparian zones are extremely important for maintaining healthy stream ecosystems. Mixed native vegetation in riparian areas provides habitat and food for mammals and other wildlife. In addition, the vegetation (particularly the root systems) reduces erosion by stabilizing streambanks, trap sediments that would otherwise enter the waterway, filter out nutrients in stormwater runoff, and provide shade, which both reduces water temperatures and increases dissolved oxygen concentrations. Therefore, a healthy riparian zone, with a mix of native tree, shrub, and herbaceous plant species, is vital for a healthy stream ecosystem and sustaining mammals and other wildlife associated with the Harpeth.

 

American Beaver – Castor canadensis

Description: The American Beaver is a semi-aquatic dark brown mammal and the largest rodent in America. They have large front teeth that are use to cut down small to medium-sized trees. They cut down trees to feed on the bark and cambium (the softer growing tissue under the bark) and to build lodges for protection and breeding. The beaver is most commonly known for its horizontally flattened, black tail that is used to help the animal swim and scare off predators. The American beaver is mostly nocturnal and most likely to be seen around sunset.

Weight: Adults usually between 26 and 70 pounds, but  documented weighing up to 90 pounds.

Body length: 34 inches to 4.5 feet (54 inches). The tail of the beaver can make up a third of body length.

Habitat: They usually inhabit rivers, creeks, or small lakes. They frequently build dams to slow the water and create favorable habitat, which puts them at risk of being harmed by humans because the dams are often considered as a nuisance.

 

North American River Otter- Lontra canadensis

Description: The North American River Otter is an aquatic predator with a life span of up to 14 years. Otters have long cylindrical bodies with webbed feet and a tapered and furry tail. The head of the otter is flat and wide with readily visible whiskers around its nose. Its body type contributes to extraordinary swimming abilities, which helps it catch the fish, crayfish, amphibians, and reptiles that make up its diet. Otter populations had declined in Tennessee due to over trapping and water pollution, but are rebounding. They are common in some rivers and streams in Tennessee, while rare in others. They are often found in families, with up to 17 otters per family. The North American River Otter is most active at night and consequently, the best time to spot this animal is at dusk or dawn.

Weight: 11 to 30 pounds with males being larger on average.

Body length: 35 inches to 53 inches. The tail ranges from 11 to 18 inches.

Habitat: They prefer rivers and streams located next to wooded areas, but also inhabit lakes. They often make dens in river banks or under tree roots.

 

American Mink – Neovison vison

Description: The mink is a small mammal with dark brown to black fur. Their oily fur provides waterproofing and changes to a lighter color in the summer months to help with the heat. The fur of the mink has always been highly valued and still is today, which puts these animals at  risk of being trapped. The mink is a very territorial animal that emits an odor to mark its territory. Fish, crustaceans, and frogs make up most of their diet. Minks are more active at night but not exclusively nocturnal. They are hard to spot because of their small size and abilities to hide.

Weight: 1 to 3 pounds.

Body Length: 12 to 27 inches. Their bushy tail accounts for roughly one third of their body length.

Habitat: The American mink are found in rivers, creeks and lakes. They preferentially build dens near fallen timber and tree roots, but will also occupy abandoned burrows of other mammals.

 

Common Muskrat- Ondatra zibethieus

Description: The Common Muskrat is a semiaquatic mammal that has brownish, black fur. It has a large head and a long, thin, rat-like tail. The vertically-flattened tail is used as a rudder and to power themselves through the water. 

Weight: 1 to 4 pounds.

Body length: 16 to 26 inches with a little less than half being made up of the tail.

Habitat: The muskrat prefers slow moving waters with easy access to vegetation. The slower moving portions of the Harpeth River are great places to spot a muskrat.

 

Woodchuck - Marmota monax

Description: The woodchuck is a medium sized animal that belongs to the squirrel family. The woodchuck has a rounded body with brown fur. The long fur with white or grey highlights, gives the woodchucks a frosted appearance. The front teeth of the woodchuck continue to grow throughout its lifespan, so they must be filed down by chewing on wood. Their diet consist of low lying vegetation and occasionally insects or bird eggs. Woodchucks build dens for hibernation in the winter and breeding in early spring.

Weight: 4 to 15 pounds.

Body length: 16 to 28 inches. The tail of the woodchuck can range from 4 to 8 inches.

Habitat: Woodchucks are found across the state of Tennessee, but they prefer cultivated fields and pastures for the abundance of food. Fields near surface waters are great spots to see a woodchuck.

 

Southern Flying Squirrel – Glaucomys volans

Description: The Southern Flying Squirrel is a very small mammal. Despite its name, these animals cannot fly, but rather use excess skin to glide from tree to tree. Upon landing, they quickly run across the tree to avoid being attacked by predators. These squirrels nest in old woodpecker holes and other tree cavities. Up to 50 squirrels can be found hibernating in the same hole to conserve heat during the winter. Their diet consists mostly of nuts and berries, but also includes insects, bird eggs, and bird nestlings. These animals are hard to spot in the wild because they are small and nocturnal. They are most often seen when building nests in bird houses at private residences.

Weight: 1 to 5 ounces.

Body Length: 8 to 12 inches.

Habitat: Southern Flying Squirrels prefer mature hardwood trees located near a water source. They need mature trees so that they have cavities for nesting and roosting.

 

Source of information

 http://www.tnwatchablewildlife.org/