Penis
Domestic cats have barbed penises, with about 120–150 one millimeter long backwards-pointing spines. Upon withdrawal of the penis, the spines rake the walls of the female's vagina, which is a trigger for ovulation. Lions also have barbed penises. Male felids urinate backwards by curving the tip of the glans penis backward. When male cheetahs urine-mark their territories, they stand one meter away from a tree or rock surface with the tail raised, pointing the penis either horizontally backward or 60° upward.
Homininae
There has been a gradual increase in brain volume (brain size) as the ancestors of modern humans progressed along the timeline of human evolution, starting from about 600 cm in "Homo habilis" up to 1500 cm in "Homo neanderthalensis". However, modern "Homo sapiens" have a brain volume slightly smaller (1250 cm) than Neanderthals, women have a brain slightly smaller than men and the Flores hominids ("Homo floresiensis"), nicknamed hobbits, had a cranial capacity of about 380 cm (considered small for a chimpanzee), about a third of the "Homo erectus" average. It is proposed that they evolved from "H. erectus" as a case of insular dwarfism. In spite of their smaller brain, there is evidence that "H. floresiensis" used fire and made stone tools at least as sophisticated as those of their proposed ancestors "H. erectus". In this case, it seems that for intelligence, the structure of the brain is more important than its size.