The most common variety of mammal on Earth are rodents. Specifically, of the approximately 6,500 known mammal species on this planet, about 40% of them are varieties of rodent. These varieties include and are not limited to mice, rats, squirrels, chipmunks, marmots, prairie dogs, gophers, beavers, and capybaras.
They also outnumber us in population too. Humans number somewhere around 8 billion, and Earth reportedly has about 7 billion rats alone before adding in the other types of rodent.
Additionally, the second most plentiful variety of mammal are bats, who make up about 20% of all known mammal species. They’re fairly closely related to rodents as well.
