Reddit mentions of A Natural History of Rape: Biological Bases of Sexual Coercion

>Animals, without a mind or conciousness, cannot rape as they do not know what that means.

This is faulty reasoning. Regardless of whether they have a moral system that considers it wrong, they do have both consensual and non-consensual sex.

http://en.wikipedia.org/wiki/Animal_sexual_behavior#Coercive_sex

Dolphins, elephants, ducks and geese have been documented doing this.

http://www.amazon.com/Natural-History-Rape-Biological-Coercion/dp/0262201259

Rape carries a reproductive advantage, allowing the rapist to pass on their genes, while not investing any effort in caring for the offspring, and bypassing the female's selection process which would normally let her pick the most suitable male.

http://en.wikipedia.org/wiki/Sociobiological_theories_of_rape

Stating that meat eating is natural is not an ethical justification. It's a behavior which has significant negative consequences, and is not necessary to living a healthy and rewarding life. It's a luxury done to satisfy a preferred taste.

You would be surprised.