Going off on a tangent for a second...
Jalexander, are you sure it wasn't a dark cougar, sometimes called a "panther"? Or was it that big? Sometimes they get coal black, here in TX. I know that we have jaguarundis here in the lower valley of TX, but Gonzales would be a tad north, wouldn't it? Also, I've not read of jaguarundi having such dark coats. [Well, wait a second, yes I have.] Was the nose pointed, like a weasel's? What was the size? Jaguarundis get to about 10 lbs, or big housecat, size.The last one is possibly the least likely, but I know what I saw. I was out with my dad and one of his cattle-raising partners on a place they had leased somewhere around Gonzales, Texas. I was in the back of the truck, and we were riding along a creek bed when I saw a black cat break out of the brush along the creek and run diagonally away from us. I yelled at my dad and he and his buddy saw it too. I'd never seen a cat like it, but dad identified it as a jaguarundi. They're strange looking critters, and supposedly the only place you can find them anymore in Texas is the very edge of the Rio Grande Valley. I'd love to see one again someday.