Summary
We examined digestibility of dry matter, nutrients, and fiber, and food intake, metabolic fecal losses, weight change, and gut size of pocket gophers (Thomomys bottae) in relation to diet quality in the laboratory. Pocket gophers were maintained for 15–20 days on one of seven diets which contained from 18% to 56% neutral detergent fiber (NDF). NDF content of the diet was an excellent predictor of diet quality. Digestibility of dry matter, NDF, and nitrogen all decreased with increasing NDF content of the diet. In general, pocket gophers compensated for low diet quality by increasing dry matter intake, but those given high quality forage before the lowest quality diet reduced their intake. Thus, the response of pocket gophers to low quality diets may depend on their body condition. Because increased food intake resulted in increased total metabolic fecal losses and metabolic fecal nitrogen losses, decreasing food intake on low-quality diets may be advantageous. A further response of pocket gophers to decreased food quality was an increase in size of cecum and large intestine, suggesting that fermentation of cell walls became increasingly important as diet quality decreased.
Similar content being viewed by others
References
Ammann AP, Cowan RL, Mothershead CL, Baumgardt BR (1973) Dry matter and energy intake in relation to digestibility in white-tailed deer. J Wildl Manage 37:195–201
Andersen DC (1982) Belowground herbivory: the adaptive geometry of geomyid burrows. Am Nat 119:18–28
Andersen DC, MacMahon JA (1981) Population dynamics and bioenergetics of a fossorial herbivore, Thomomys talpoides (Rodentia: Geomyidae), in a spruce-fir sere. Ecol Monogr 51:179–202
Baile CA, Forbes JM (1974) Control of feed intake and regulation of energy balance in ruminants. Physiol Rev 54:160–214
Bandoli JH (1981) Factors influencing seasonal activity in the pocket gopher, Thomomys bottae. J Mammal 62:293–303
Batzli GO, Cole FR (1979) Nutritional ecology of microtine rodents: digestibility of forage. J Mammal 60:740–750
Blaxter KL, Mitchell HH (1948) The factorization of the protein requirements of ruminants and of the protein values of feeds, with particular reference to the significance of the metabolic fecal nitrogen. J Anim Sci 7:351–372
Burton DH, Black HC (1978) Feeding habits of Mazama pocket gophers in south-central Oregon. J Wildl Manage 42:383–390
Chase JD, Howard WE, Roseberry JT (1982) Pocket gophers (Geomyidae). In.: Chapman JA, Feldhamer GA (eds) Wild mammals of North America. Biology, Management and Economics. Johns Hopkins Univ Press, pp 239–255
Cochran WG, Cox GM (1957) Experimental designs. 2nd ed. Wiley, New York
Cork SJ, Kenagy GJ (1989) Nutritional value of hypogeous fungus for a forest-dwelling ground squirrel. Ecology 70:577–586
Cox GW (1989) Early summer diet and food preferences of northern pocket gophers in north central Oregon. Northwest Sci 63:77–82
Dalton DC (1963) Effect of dilution of the diet with an indigestible filler on feed intake in the mouse. Nature 197:909–910
Demment MW (1983) Feeding ecology and the evolution of body size of baboons. Afr J Ecol 21:219–233
Demment MW, Van Soest PJ (1985) A nutritional explanation for body-size patterns of ruminant and non-ruminant herbiyores. Am Nat 125:641–672
Garrison MV, Reid RL, Fawley P, Breidenstein CP (1978) Comparative digestibility of acid detergent fiber by laboratory albino and wild Polynesian rats. J Nutr 108:191–195
Gettinger RD (1984a) Energy and water metabolism of free ranging pocket gophers, Thomomys bottae. Ecology 65:740–751
Gettinger RD (1984b) Seasonal patterns of nitrogen utilization by pocket gophers, Thomomys bottae. Comp Biochem Physiol 78A:657–659
Green DA, Millar JS (1987) Changes in gut dimensions and capacity of Peromyscus maniculatus relative to diet quality and energy needs. Can J Zool 65:2159–2162
Gross JE, Wang Z, Wunder BA (1985) Effects of food quality and energy needs: changes in gut morphology and capacity of Microtus ochrogaster. J Mammal 66:661–667
Hoover WH, Heitman RN (1972) Effects of dietary fiber levels on weight gain, cecal volume and volatile fatty acid production in rabbits. J Nutr 102:375–380
Jenkins SH, Bollinger PW (1989) An experimental test of diet selection by the pocket gopher Thomomys monticola. J Mammal 70:406–412
Keith JO, Hansen RM, Ward AL (1959) Effect of 2,4-D on abundance and foods of pocket gophers. J Wildl Manage 23:137–145
Mattson WJ, Jr (1980) Herbivory in relation to plant nitrogen content. Ann Rev Ecol Syst 11:119–161
Montgomery MJ, Baumgardt BR (1965) Regulation of food intake in ruminants. 1. Pelleted rations varying in energy concentration. J Dairy Sci 48:569–574
Parra P (1978) Comparison of foregut and hindgut fermentation in herbivores. In: Montgomery GG (ed) The ecology of arboreal folivores. Smithsonian Inst Press, Washington, DC, pp 205–209
Peterson AD, Baumgardt BR (1971) Influence of level of energy demand on the ability of rats to compensate for diet dilution. J Nutr 101:1069–1074
Robbins CT (1983) Wildlife feeding and nutrition. Academic Press, New York, p 343
Robertson JB, Van Soest PJ (1980) The detergent system of analysis and its application to human foods. In: James WPT, Theander O (eds) The analysis of dietary fiber and food. Marcel Dekker, New York, pp 123–158
SAS Institute (1985) SAS User's Guide: Statistics, Ver 5. SAS Institute Inc, Cary, North Carolina p 956
Shenk JS, Elliott FC, Thomas JW (1970) Meadow vole nutrition studies with semisynthetic diets. J Nutr 100:1437–1446
Shenk JS, Elliott FC, Thomas JW (1971) Meadow vole nutrition studies with alfalfa diets. J Nutr 101:1367–1372
Sinclair ARE, Krebs CJ, Smith JNM (1982) Diet quality and food limitation in herbivores: the case of the snowshoe hare. Can J Zool 60:889–897
Van Soest PJ (1967) Development of a comprehensive system of feed analyses and its application to forages. J Anim Sci 26:119–128
Van Soest PJ (1982) Nutritional ecology of the ruminant. O & B Books, Corvallis, OR, p 374
Van Soest PJ, Foose T, Robertson JB (1983) Comparative digestive capacities of herbivorous animals. Proc Cornell Nutr Conf, pp. 51–59
Vaughan TA (1967) Food habits of the northern pocket gopher on shortgrass prairie. Am Midl Nat 77:176–189
Vleck D (1979) The energy cost of burrowing by the pocket gopher Thomomys bottae. Physiol Zool 52:122–136
Vleck D (1981) Burrow structure and foraging costs in the fossorial rodent, Thomomys bottae. Oecologia (Berlin) 49:391–396
Webster AJF (1981) The energetic efficiency of metabolism. Proc Nutr Soc 40:121–128
White TCR (1978) The importance of a relative shortage of food in animal ecology. Oecologia 33:71–86
Williams LR, Cameron GN (1986) Food habits and dietary preferences of Attwater's pocket gopher, (Geomys attwateri). J Mammal 67:489–496
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Loeb, S.C., Schwab, R.G. & Demment, M.W. Responses of pocket gophers (Thomomys bottae) to changes in diet quality. Oecologia 86, 542–551 (1991). https://doi.org/10.1007/BF00318321
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00318321