You'd normally expect to see deer in fields, woods or parks, but more and more of them are now exploring towns and cities, and causing chaos!
They've been spotted on roundabouts, in cemeteries and on golf courses.
Among their crimes, they are responsible for causing 74,000 road accidents every year.
The problem's so bad some fire station staff in the UK are even being taught how to deal with emergency call-outs involving the disruptive animals.
Latest figures say there are two million deer in the UK - the highest level for 1,000 years.
As well as the causing a lot of road accidents, they are also known for destroying plants, trees and spreading disease.
The deer population appears to be growing fast in towns and cities and unlike deer in rural areas, it is much harder to control urban numbers by culling them.
Many people think that, just like foxes and squirrels, it will become more and more common to see deer wandering around in a town near you!