A river otter stands up after hitting the waterslide at Ichikawa Zoological and Botanical Garden in Ichikawa, east of Tokyo, Wednesday, July 30, 2014. Playful otters spend their time swimming and playing in the waterslide that was built two years ago in commemoration of the 25th anniversary of the zoo for the mammals to beat the summer heat.
A river otter is any of 13 living species of semiaquatic (or in the case of the sea otter, aquatic) mammals that feed on fish and shellfish, and also other invertebrates, amphibians, birds and small mammals. An otter's den is called a holt or couch. A male otter is a meowter, a female is a queen, and a baby is a pup. The collective nouns for otters are bevy, family, lodge, or romp, (being descriptive of their often playful nature) or, when in water, raft.