Protection from the elements:
* Warmth: Otters are semi-aquatic mammals and need to stay warm, especially in colder climates. Their dens need to be insulated and protect them from wind, rain, and snow.
* Dryness: Otters have a thick fur coat, but they still need to stay dry to avoid getting hypothermia. Their dens should be located in areas that are well-drained and don't flood easily.
* Protection from predators: Otters are vulnerable to predators both on land and in water. Their dens should be located in areas that are difficult for predators to access.
A place to raise young:
* Safe haven: Otters typically raise their young in dens. These dens need to be safe from predators and other threats.
* Space for pups: The dens should be large enough to accommodate the mother otter and her pups.
Types of shelters:
Otters use a variety of shelters, depending on the species and the location.
* Dens: Otters often dig burrows in the banks of rivers, lakes, and streams. These burrows can be quite extensive and may have multiple entrances.
* Tree hollows: Some otters, like sea otters, use tree hollows for shelter.
* Rock crevices: In some areas, otters may use rock crevices or caves for shelter.
* Underwater burrows: Some species, like river otters, may dig underwater burrows in muddy banks.
* Driftwood piles: Sea otters sometimes use driftwood piles for shelter.
Specific needs:
* Sea otters: These otters are more vulnerable to the cold and need to be able to float on their backs to groom their fur. They often use kelp forests and driftwood piles for shelter.
* River otters: These otters need access to water and often use burrows near rivers and streams.
* Sea otters: They are unique in that they are the only marine mammal known to use tools. They often use rocks to break open shellfish for food.
It's important to note that otters are adaptable animals and may use a variety of different shelters, depending on their environment and the resources available to them.