I love cats.  I have a house cat now, a grey short haired cat. 
I do too! He's grey and white! He's a typical house cat. He's strictly kept indoors.
I keep mine totally indoors too.  I wonder when were cats domesticated. 
I'm not sure, but it has to be a long time! I wish I could see in near darkness like my cat! They have amazing senses.
Are cats good hunters because they have good senses? 
Yes, they are excellent hunters! They can hear sounds that are too faint or high pitched for humans to hear! That's how they're able to catch mice and other small animals.
I wonder if cats have to be kept in check because they deplete natural animals in the environment. 
They do have a high breeding rate and their quick reflexes, sharp claws, and strong flexile bodies make them quite the predator!
I bet they have caused some species of animals to go extinct. 
I'm sure they have! There are more than seventy breeds of cat, that's a lot of felines out there killing little animals!