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-to-body mass ratio
Dolphins have the highest brain-to-body weight ratio of all cetaceans. Monitor lizards, tegus and anoles and some tortoise species have the largest among reptiles. Among birds, the highest brain-to-body ratios are found among parrots, crows, magpies, jays and ravens. Among amphibians, the studies are still limited. Either octopuses or jumping spiders have some of the highest for an invertebrate, although some ant species have 14%-15% of their mass in their brains, the highest value known for any animal. Sharks have one of the highest for fish alongside manta rays (although the electrogenic elephantfish has a ratio nearly 80 times higher - about 1/32, which is slightly higher than that for humans). Treeshrews have a higher brain to body mass ratio than any other mammal, including humans. Shrews hold about 10% of their body mass in their brain.