. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 160 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY Vol. 124 provided with all they could eat (12,000 calories/day) and they gained up to 25 kg in two months. It appears that this is not unlike the weight cycle seen in the wild, for on September 1 I have seen bears with over 5 cm of subcutaneous fat and great masses of depot fat. Dv. Robert Rausch of the Arctic Health Research Center has provided data on a four-year old male brown bear which he collected on Kodiak Island on September 10, 1952. Total weight was 195 kg, and fat
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 160 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY Vol. 124 provided with all they could eat (12,000 calories/day) and they gained up to 25 kg in two months. It appears that this is not unlike the weight cycle seen in the wild, for on September 1 I have seen bears with over 5 cm of subcutaneous fat and great masses of depot fat. Dv. Robert Rausch of the Arctic Health Research Center has provided data on a four-year old male brown bear which he collected on Kodiak Island on September 10, 1952. Total weight was 195 kg, and fat weighing 20 kg was removed. It was estimated that total fat weighed about 30 to 32 kg, or that 16 per cent of the weight was fat. Subcutaneous fat varied in thickness from 40 to 53 mm over the hind quarters. 4 10- 400- 39 0 o o 380- ; 2 370- 36 0- 35 0- 34 0- 330- X' AVE RAGE FOR DATE. 20 30 10 20 APR MAY 30 10 20 JUNE 30 10 20 30 JULY 10 20 30 AUG 10 20 30 10 SEPT OCT Pig. against 5. Rectal temperatures of wild Arctic ground squirrels plotted date. Five years are represented. It appears that wild black bears may lose up to 20 to 30 kg during the winter denning period. Assuming the average adult weight to be 1 ">(• kg, this would be a loss of about 15-20 per cent of their weight. (1 round squirrels lose nearly 30 per cent, although their torpor is more profound. This difference in percentage weight loss is probably due to the great difference in total body mass of the bear and ground squirrel, and is in itself tribute to the efficiency of deep hibernation. Body Temperal ure Variation It has Long been stated that hibernators have a greater lability of temperature while active than that found in homeotherms (Johnson, 1931 ; Cielineo, 1938). However, in the course of other. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly
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