Virginia opossum

Virginia opossums can vary considerably in size, with larger specimens found to the north of the opossum's range and smaller specimens in the tropics. They measure 13–37 in (35–94 cm) long from their snout to the base of the tail, with the tail adding another 8.5–19 in (21.6–47 cm). Weight for males ranges from 1.7 to 14 lb (0.8–6.4 kg) and for females from 11 ounces to 8.2 lb (0.3–3.7 kg). They are one of the world's most variably sized mammals, since a large male from northern North America weighs about 20 times as much as a small female from the tropics. Their coats are a dull grayish brown, other than on their faces, which are white. Opossums have long, hairless, prehensile tails, which can be used to grab branches and carry small objects. They also have hairless ears and a long, flat nose. Opossums have 50 teeth, more than any other North American land mammal, and opposable, clawless thumbs on their rear limbs. The dental formula of an opossum is 5134/4134. No other mammal in North America has more than 6 upper incisors, but the Virginia opossum has 10. Opossums have 13 nipples, arranged in a circle of 12 with one in the middle. Perhaps surprisingly for such a widespread and successful species, the Virginia opossum has one of the lowest encephalization quotients of any marsupial. Its brain is one-fifth the size of a raccoon's.