How many native and introduced mammal species live in the UK?

The UK is home to around 50 native mammal species, including well-known animals like red deer, hedgehogs, and badgers. In addition, there are approximately 20 introduced mammal species, such as the gray squirrel and the muntjac deer. These introduced species can sometimes impact local ecosystems and native wildlife. Overall, the diversity of mammals in the UK reflects a mix of its natural heritage and human influence.