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.
Brain size
The volume of the human braincase has increased as humans have evolved (see Homininae), starting from about 600 cm in "Homo habilis" up to 1740 cm in "Homo neanderthalensis", which was the hominin with the biggest brain size.