9. Least Weasel (Mustela nivalis)
The least weasel is the world’s smallest carnivore, occurring throughout Eurasia, North America and North Africa. They can weigh as little as 1.04 ounces (29.5 grams) or as much as 8.8 ounces (250 grams). Their size is also very variable, but they can be as small as 5 inches (131 millimeters) long, including the tail! Don’t let that fool you—despite their petite size, they are formidable and fierce hunters.