There is an small brown furry animal behind my house in Indianapolis. I have seen him both on land and in the water. what could it be?
Beaver possibly.. Look up small mammals online
Could be a beaver,, or a groundhog.
It could be an otter
Probably a muskrat - which is much smaller than a beaver. Beavers are fairly large.
The only brown mammal to be in both the water and the backyard is none other than the Sasquatch... Set up a camera (make sure its blurry) and get some low res pictures preferably at night time or very early morning.
A beaver ? Maybe it's still young
Probably a ground hog. They can get really big. They like to live in burrows or banks.