The Cycle of the Year 
59 
THE TEMPERATURE OF THE HIVE 
In a study of the activities of a colony of bees, the question 
of temperature must be carefully considered. Bees are cold¬ 
blooded (poikilothermous) animals, that is, the temperature 
of the body of an individual bee is variable and is the same 
or almost the same as that of the air immediately surround¬ 
ing the body. All cold-blooded animals usually have a 
temperature slightly above that of the surrounding medium, 
except in the case of animals having a moist skin and sur¬ 
rounded by air, in which evaporation on the surface of the 
body may cause the temperature of the body to fall a little 
below that of the air. The heat which raises the tempera¬ 
ture of the individual bee, and collectively of the bee colony, 
above that of the surrounding air is generated chiefly by 
muscular activity. The individual bee can continue mus¬ 
cular movements only so long as the temperature of the body 
does not fall below 45° F., but at about this temperature it 
loses its power of movement. The highest temperature at 
which bees can live has not been accurately determined but 
it must be over 130° F. 
While the individual bee does not possess the ability to 
maintain a nearly uniform body temperature, as do warm¬ 
blooded animals, the colony as a whole shows some remark¬ 
able temperature changes, different from any observed in 
individual bees or in other cold-blooded animals. Warm¬ 
blooded animals maintain a fairly constant temperature 
which may be either higher or lower than that of the sur¬ 
rounding air. While the colony of bees may maintain a 
temperature either warmer or colder than the surrounding 
air (colder than the air outside the hive), the temperature 
of the colony is not constant. In warm-blooded animals, 
most of the heat is generated by the processes of internal 
combustion in the assimilation of food, augmented by heat 
due to muscular activity. In the bee, the chief method of 
heat production is by muscular activity, with possibly some 
additional heat from other life processes, and the bee, unlike 
