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River Otter Observation Form
River Otter Observation Form
River otter in water. Taken by Steve Blue.

​​​​​​​​​Have you seen an otter?

River Otter River otters are semi-aquatic members of the weasel family. They have long, torpedo-shaped bodies with short legs, a short snout and small, round ears. They have light to dark brown fur that can appear almost black when wet, and a silver-brown underbelly. Otters weigh between 15 and 25 lbs. They are about 3 to 4 1/2 feet in length from their nose to the tip of their long furry, cylindrical tail. Their thick, muscular tail tapers toward the tip, and comprises about one-third of their length, at 12" to 17".

Several Colorado mammals, including mink, beaver and muskrats, share the same habitat as river otters and are commonly confused with otters. All have dark brown fur and can be particularly difficult to distinguish from each other when they are swimming on the surface, partially submerged, especially when viewed from a distance. When viewed on land, however, their body shape, weight, size and tails are all quite distinctive.

For more information, including a section on "commonly confused with...", see the River Otter Species Profile​.​​​

Please complete the following questions if you've seen a river otter in Colorado.
Your answers will be used to help the river otter conservation program.

First Name*required

Last Name*required

Email Address*required


May we contact you for additional information?

Date and time of observation:

Describe exact location of observation:
Please include county and nearby landmarks. List township/range/section or
if using GPS coordinates, please use UTM coordinates and provide the Datum and Zone, if available.

Describe the otter’s physical characteristics:
Please include an estimate of the body length and approximate weight of the animal.

Describe the otter’s activities you observed:

Distance from you to the otters:

Number and Age of Otters:
How many otters did you see?

Did you see adults or juveniles?

Name of water body:

Habitat Description:

Additional Comments:

Did you take photos?