Like all endangered and threatened species, otters are protected by closed hunting and trapping seasons. Habitat Rivers, streams and lakes are key habitats. Those with wooded shorelines and nearby wetlands are best. Water quality isn't a major concern unless it's so bad that fish are scarce. Some types of contaminants can cause problems, but tests show that otters from Illinois have little or no accumulation of these compounds in their bodies.
Beavers tend to make areas even more inviting for otters.
For example, otters aren't able to dig their own burrows, so abandoned beaver dens are their favorite places for resting and raising young. Pools and wetlands created by beaver dams are good places for otters to search for food. Habits River otters are most active at night. Adult males live along large stretches of river, often up to 40-50 miles in length. Females aren't nearly as mobile.