Certain rodents are small mammals of the order Rodentia, which includes mice, rats, squirrels, and porcupines. Mice are one of the most common and widespread species of rodent, found in almost every habitat on Earth. They are known for their small size, long tails, and large ears. Mice are omnivorous, eating both plant and animal matter, and they are often used in scientific research due to their ease of handling and breeding.