It's funny. Even in 2019 the dictionary still hasn't decided and instead has listed both mouses and mice. LOL! Look at #4.
mouse (mous)
n. pl. mice (mīs)
1.
a. Any of numerous small rodents of the families Muridae and Cricetidae, such as the house mouse, characteristically having a pointed snout, small rounded ears, and a long naked or almost hairless tail.
b. Any of various similar or related animals, such as the jumping mouse, the vole, or the jerboa.
2. A cowardly or timid person.
3. Informal A discolored swelling under the eye caused by a blow; a black eye.
4. pl. mice or mous·es (mous′ĭz) Computers A handheld, button-activated input device that when rolled along a flat surface directs an indicator to move correspondingly about a computer screen, allowing the operator to move the indicator freely, as to select operations or manipulate text or graphics.