Lutra is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of otter

Otter

The Otters are twelve species of semi-aquatic mammals which feed on fish and shellfish, and also other invertebrates, amphibians, birds and small mammals....

s.

• Lutra nippon - Japanese otter
• Lutra sumatrana - Hairy-nosed otter
• Lutra lutra - European otter

Habitat

Lutra are semi-aquatic mammals and therefore need to be well-adapted to both water and land. They prefer shallow, narrow areas of streams surrounded by mature trees and with rocks, especially where weirs reduced the flow of the water as well as attracted fishes. They seem to tolerate roads, residential and agricultural areas, but only moderate human interaction. They clearly avoid areas without vegetation cover and rocks.

Diet

The otter's diet consists mainly of fish (Hence, the aquatic environment). However, during the winter and in colder environments fish consumption is significantly lower and the otters use other resources for their food supply. Their diet can consist of amphibians (mainly frogs and pond turtle), bird predation (mainly anserine species), small rodents, and invertebrates like water beetles, snails and crayfish. They have also fed on plants, specifically grasses. Its with this large diversity of prey and resources for their diet, that otters are considered "opportunistic eaters".