Effects of fasting and refeeding on body composition of captive gray wolves ( Canis lupus )

• Published in: Canadian Journal of Zoology
• Main Authors: Kreeger, T. J., DelGiudice, G. D., Mech, L. D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1997
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Canis lupus
• Online Access: http://dx.doi.org/10.1139/z97-781; http://www.nrcresearchpress.com/doi/pdf/10.1139/z97-781

We examined the effects of fasting and refeeding on body composition in 9 captive adult gray wolves, Canis lupus (6 males, 3 females), during May–June 1995. Body composition was estimated by the technique of tritiated water dilution. Wolves were immobilized and weighed, base-line blood samples were taken, tritiated water was injected, and additional blood samples were taken before fasting, after 10 d of fasting, and again after 2 d of refeeding. Male wolves lost 8% (P = 0.0001) and females lost 7% body mass (P = 0.01) during the 10 d. Males lost 54% of this mass in water, 28% in fat, and 18% in protein/ash; females lost 58% in water, 20% in fat, and 22% in protein/ash. Upon refeeding, male wolves consumed an average of 6.8 kg (15.3% body mass) of deer meat per day and females consumed 6.4 kg (18.7% body mass). All wolves regained their initial mass. Males regained 24% of this mass in water, 70% in fat, and 6% in protein/ash; females regained 35% in water, 51% in fat, and 14% in protein/ash. This study provided evidence that after prolonged fasting, captive wolves could quickly and efficiently regain lost body mass after refeeding.