Colorado Parks and Wildlife is turning to the public for help mapping river otter populations statewide, launching a community science initiative called Otter Y.E.A.R. (Yearlong Engagement and Assessment of River Otters) to mark the 50th anniversary of river otter reintroduction in Colorado.
The project lives on the iNaturalist platform, where residents and visitors can submit photos and location data of river otters or signs of their presence, including tracks and scat. CPW staff and partner organizations will run parallel surveys on the Yampa, Green, Colorado, and Gunnison Rivers throughout the year.
River otters were once common across Colorado’s major river systems before being wiped out by the early 1900s, casualties of unregulated hunting and widespread water pollution. The Colorado Division of Wildlife reintroduced 120 animals between 1976 and 1991, and the population has rebounded meaningfully since.
“Coloradans who enjoy river otters today have that opportunity because of the vision and dedicated work 50 years ago by Division of Wildlife employees and several graduate students, along with the Pittman-Robertson dollars used to fund the effort. This year’s survey will help us understand the extent of reintroduction success and any limitations to it.” – River Otter Program Manager Bob Inman.
Data collected in 2026 will inform future conservation decisions, including potential reintroduction into suitable habitat that currently lacks otters.
Participants whose photos stand out may be featured in CPW’s monthly “Otter Photo of the Month” social media highlights. To get involved, download the free iNaturalist app, search for the “Otter Y.E.A.R. 2026” project, and submit observations with location details included.
