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.
Human brain
The adult human brain weighs on average about which is about 2% of the total body weight, with a volume of around 1260 cm in men and 1130 cm in women, although there is substantial individual variation. Neurological differences between the sexes have not been shown to correlate in any simple way with IQ or other measures of cognitive performance.