Mandrills are the largest and most colorful of the Old World monkeys. They are related to baboons and even more so to drills. Their furry head crest, mane, and beard are quite impressive. But what grabs your attention is their bright coloration. They have thick ridges along the nose that are purple and blue, red lips and nose, and a golden beard. An adult male mandrill with the brightest and most distinctive colors on his face seems to be most attractive to females. But that's not all—those bright colors show up again on the mandrill’s rear end! Why? Well, those colors impress the ladies. And, they help mandrills to follow each other in thick forests.