Freshwater Mammals

Beaver dam
Beaver Dam

An assortment of mammals that might be observed in and around the water.


Muskrat

Ondatra zibethica

Size: to 14" (body)

Habitat: in and around water

Notes:
Muskrats sometimes build a water "house", like a beaver, although they don't build dams. Common anywhere there is suitable watery habitat.


Beaver

Castor canadensis

Size: 3-4 ft ( total length )

Habitat: in and around water

Notes:
Famous for their dam-building habits, beavers were once a major ecological force in North America, reshaping a very large proportion of the land to suit themselves. Unfortunately for them, they also became a major economic force - much of the early exploration of the continent was done by fur trappers. Today, beavers are rare, and virtually non-existent in New Jersey, although there are a few colonies.


Otter

Lutra canadensis

Size: to 30" (body)

Habitat: in and around water

Notes:
River otters are shy but playful creatures that spend much of their time just splashing around. They don't like human encroachment and are uncommon nowadays.


Norway Rat

Rattus norvegicus

Size: 6-8" (body)

Habitat: everywhere

Notes:
Sorry to say, but rats are especially common around watery habitats and are excellent swimmers. They are particularly fond of beaches, marshes, ships, docks, and jetties. The next time you go diving at Shark River, take a careful look in the rocks and you will likely see one or two scampering around, dining on old fishing bait and washed-up detritus, even in broad daylight. The Norway Rat is introduced from the Old World, and in most areas today it is more common than the native Black Rat.


Raccoon

Procyon lotor
( literally: pre-dog washer )

Size: 3 ft ( total length )

Habitat: around water

Notes: Raccoons are not really aquatic. They like to live around water so that they can dunk their food. Maybe they're washing it, or maybe they just like wet food, but they will use any water that is handy - a birdbath, swimming pool, or dog dish will do in a pinch.


Stargazer

Astroscopus guttatus

Size
to 22" and 20 lbs.

Description:
Don't expect to see these fishes very often - they live buried in the sand, with just their eyes protruding. The eyes are directly atop the flat head, and the mouth is almost vertical. Of course, they are ambush predators. If you flush one from its hiding place, it will clumsily swim a short distance, and then rebury itself in just seconds. Stargazers are capable of producing weak electric currents from organs located behind the eyes. I doubt that it is enough to be dangerous to a diver, although it might be startling! Midshipmen are similar but smaller, with a continuous dorsal fin and luminescent spots instead of electrical organs.