Honey bee workers keep the hive temperature uniform in the critical brood area (where new bees are raised). This is in the centre frames of the brood box. Workers must maintain the hive's brood chamber at 34.4 °C to incubate the eggs. If it is too hot, they collect water and deposit it around the hive, then fan air through with their wings causing cooling by evaporation. If it is too cold, they cluster together to generate body heat. This is an example of homeostasis.