Some are. The North American Cougar is more closely related to the house cat than any other species, and they exhibit many of the same traits. The Cougar. like the house cat, prefers to eat the organs of its prey while it is still alive. Some sources say that it is like ice cream to the big cats.
More big cat facts: http://www.wwbrock.com/COUGAR/index3.html
Things tend to end badly for people who keep cougars as pets.