Definately a Beaver.
Beavers have broad flat tails that they use to splash the water when they're in danger which alert other beavers about it. Otters's tail are rounded.
A bank beaver is a US dialect term for an otter.
With their dams
dams
Well man made dams like the Hoover dam can support the water from overflowing while beaver dams a just basically homes.
beaver
No but a Weasle,Mink is...
because there cool like that
It builds dams
Historical siginifigance
Freshwater Fish and snails, and also Beavers.
Sarah Anne Curzon has written: 'Laura Secord, the heroine of 1812' -- subject(s): Beaver Dams, Battle of, Beaver Dams, Ont., 1813, Drama 'The story of Laura Secord, 1813' -- subject(s): Biography, History, Beaver Dams, Battle of, Beaver Dams, Ont., 1813, Canada War of 1812