A shoe has a flexible elastic sole and a vamp for fixing the sole to the foot of an animal. The flexible elastic sole has a through-hole in a bottom part thereof for allowing air to be pushed out from an interior space of the shoe when a middle part of the sole is pressed towards the foot. The interior space is defined by a space in between the foot and said sole, and allows air to be sucked in from an exterior of the shoe when the middle part of the sole moves away from the foot under elastic forces acting on the sole.
