Men will be happy to know that humans have the largest primate penis with respect to overall body size. Gorillas oddly enough have one of the smallest primate penises, despite the fact that they are the largest primates on Earth. Gorillas penis size averages around a paltry two inches. Chimpanzees are much smaller than gorillas, yet sport a penis twice as long…
Source:
http://www.associatedcontent.com/article/194655/penis_size_in_the_animal_kingdom.html