North American river otter

Description:

These aquatic mammals are so fun to watch and study. The ears are short, the neck is the same diameter as the head, the legs are short and powerful, the toes are fully webbed, and the tail (one-third of body length) is tapered. These qualities give the North American river otter a streamlined profile in water, but reduce agility on land. The smell and hearing abilities of the North American river otter are acute. The North American river otter has a delicate sense of touch in the paws in addition to great dexterity. North American river otters characteristically approach within a few feet of a boat or a person on shore because they're near-sighted, a consequence of vision adapted for underwater sight. North American river otters have transparent nictitating membranes to protect their eyes while swimming. I was amazed by their ability to follow me as I walked along the bank (trying to hide behind trees in camouflaged clothing). Every time they came up out of the water they knew exactly where I was at.

Habitat:

Spotted in a back water slough of the Columbia river at the Ridgefield National Wildlife Refuge.

Notes:

Communication among North American river otters is accomplished mainly by olfactory and auditory signals. Scent marking is imperative for intergroup communication. The North American river otter scent-marks with feces, urine, and possibly anal sac secretions. Musk from the scent glands may also be secreted when otters are frightened or angry. North American river otters can produce a snarling growl or hissing bark when bothered, and a shrill whistle when in pain. When at play or traveling, they sometimes give off low, purring grunts. The alarm call, given when shocked or distressed by potential danger, is an explosive snort, made by expelling air through the nostrils. North American river otters also may use a birdlike chirp for communication over longer distances, but the most common sound heard among a group of otters is low-frequency chuckling.