Minecraft wiki entry for Fox, associated text: During the day, if a thunderstorm is not occurring, foxes attempt to find a space with a sky light level of 14 or less and sleep. Block light has no effect on this. While it sleeps, it slowly moves its head up and down. A fox wakes if approached by a player or mob. Foxes do not flee if the player approaches while sneaking until the player gets on an adjacent block.