I saw a small mammal in PR that looked like a river rat, only smaller, can anyone help identify it?

I recently relocated to Puerto Rico, and while on the north-eastern coast, at a restaurant, I spotted a pair of mammals, larger than a squirrel, but smaller than an otter. I believe it to be amphibious. It was dark brown (almost black, as it also looked wet), with a large hairless tail, like a rat, but was NOT a rat. Can anyone help identify this creature? Lead me to a website, to see photos? One person in my group suggested it was a 'Puerto Rican Squirrel', but my investigation has shown there are no such creatures here. I do know that mongoose where brought here many years ago, to help with rats in the Suger plantations, but both are long gone (rats %26amp; mongoose).I saw a small mammal in PR that looked like a river rat, only smaller, can anyone help identify it?
It was a Muskrat, go here to see pictures...



http://www.1000birds.com/latest20050326M鈥?/a>



http://www.redpath-museum.mcgill.ca/Qbp/鈥?/a>



http://www.pbase.com/muskrat/image/26663鈥?/a>



http://www.hww.ca/hww2.asp?id=96



http://museum.nhm.uga.edu/gawildlife/mam鈥?/a> (roundtail muskrat)



Edit, here is a really great site with lots of photos and information... http://my.net-link.net/~vaneselk/muskrat鈥?/a>
chupacabraI saw a small mammal in PR that looked like a river rat, only smaller, can anyone help identify it?
Sir, the answer is you,your wife and children. I called Secretary of Agriculture in Porto Rico and stated they have pictures of these creatures,it was "YOU". Sorry for the bad news but now you don't have to look any farther.
Yes they are there still. Mongoose, rats, lots of other things.



It's in the island's rainsforest mostly but check it out at http://wfcb.ucdavis.edu/www/Faculty/desl鈥?/a>
Click here: http://en.wikipedia.org/wiki/Rodentia
Maybe a muskrat?