The gross mass, mean adipocyte volume and activities of hexokinase (HK) and phosphofructokinase (PFK) were measured in adipose tissue from precisely identified intermuscular, superficial and intra-abdominal depots of 56 randomly collected wild and captive mammals and one bird. 2. In all intermuscular depots studied except that medial to the trapezius muscle, the activities of HK and PFK per adipocyte in adipose tissue in the centre of the depot were greater than in superficial and intra-abdominal depots of the same specimen. 3. These data are consistent with the suggestion that intermuscular adipose tissue may act as a local energy supply for adjacent muscles.