The heat level drops if activity in the area ceases. Your heat map rises when you perform various activities, campfires and forges may raise it, as can cutting trees, mining, using certain weapons, explosives, the Augur or even crafting. If they detect you, they will scream and a horde will spawn.
![7 days to die zombie spawn rate 7 days to die zombie spawn rate](https://i.ytimg.com/an/uJb2U8gZ15o/441272b7-c2ce-464c-945c-d139219126f4_mq.jpg)
When you produce a certain amount of " heat", a Screamer or two will spawn to investigate.
![7 days to die zombie spawn rate 7 days to die zombie spawn rate](https://i.ytimg.com/vi/W4MubvSlYPc/maxresdefault.jpg)
Note: Zombies have been placed in the Normal List until information regarding their uniqueness comes to light. They can be rather easily defeated with basic weapons, but can pose a challenge to new characters especially in packs or in close quarters inside buildings. Normal zombies are the ones a player usually faces when exploring the world.