Purr

I have always thought a cats purr was fascinating. Cats don't just purr when they are happy. They purr with other emotions as well. They will purr when they have an injury or experienced a traumatic moment, even near death. There is even a theory that purring helps with pain. Finding this out it makes me wonder if Simba is in pain all the time or is he just happy. Other animals other then a cat that purr as well. There is about 15 species that purr, such as a Raccoon.
http://cats.about.com/cs/catmanagement101/a/why_cats_purr.htm 
Syufy, Franny. Why and How Do Cats Puff. About. N.p. n.d. Web. 19 Oct. 2014.

I found this video that will explain more on how cats purr.
https://www.youtube.com/watch?v=eHZJrx7RZ2w

Simba is becoming more and more affectionate. Maybe he is be coming in heat. He has been laying on his sister and biting her neck and from years of having cats I know that's an intimate sign. I think that's gross so I pull him off her. Maybe she is the one in heat and he is reacting to her. I notice that he purrs really loud when he is being intimate with her. Maybe his purr is a way of showing affection. I'm planning on really listening to each time he purrs because maybe a cats purr has a different tone based on their mood or during a certain situation.

Work cited

Syufy, Franny. Why and How Do Cats Puff. About. N.p. n.d. Web. 19 Oct. 2014.