Assertion: piranha's tail | /r/ObjectUse | used as rudder
Facets:
value: in the water
type: LOCATION
Source sentences:
text: River otters are long-bodied, well-muscled animals, with relatively short legs, five webbed toes on all four feet, (most carnivores have 4 toes on the rear foot), and a long flat tail used as a rudder in the water.