It might be an otter.
a rat.
Capybara
Capybara
chinchla
You might be referring to the tapir, a South American rodent (the world's largest rodent) that looks very much like a "five foot rat".
There is an animal that looks like a beaver but the tail is more like a rat tail and it is called a Nutria.
parson
Likely large roof rats or wharf rats. They get rather large, perhaps larger than you thought a rat would be.
Although the name makes it sound like a large animal, the giant kangaroo rat is very small. It is preyed upon by larger mammals, such as kit fox and coyote.
A rat! I know what a rat looks like this was no rat to big sleek and fat
Probably some species of opossum. But if you were near a wharf, it may have been a well-fed wharf rat. They can get a body the size of a football.
No because a mouse looks like a rat but it isn't a rat isn't it?