waterdog
/ˈwɔːtərˌdɔɡ/Definitions
1. noun
a type of otter, particularly the North American river otter (Lontra canadensis) or the Eurasian otter (Lutra lutra), that is often referred to as a water dog due to its aquatic habits and dog-like appearance
“The waterdog swam effortlessly through the river, its sleek fur glistening in the sunlight.”