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.
Southern grasshopper mouse
Relative brain size tends to vary with food preferences. Brain size is usually smallest in folivores, larger in both granivores and insectivores, and largest in generalists. Measurements of cranial volume of museum specimens of southern grasshopper mouse have shown that on average, females were heavier and longer than males, but their cranial volume was about 3% less than that of males. However, this was not a significant difference. This pattern of brain-body relationship can also be seen in northern grasshopper mice. Moreover, the tail length of southern grasshopper mice made up an average of 33.9% of its body length. Their tail length measures an average of 4.58 ± 0.36 cm in females, and 4.50 ± 0.39 cm in males. Average tail length does not vary greatly between the sexes.