FIBER UTILIZATION BY KALAHARI DWELLING SUBTERRANEAN DAMARA MOLE-RATS (CRYPTOMYS DAMARENSIS) WHEN FED THEIR NATURAL DIET OF GEMSBOK CUCUMBERTUBERS (ACANTHOSICYOS-NAUDINIANUS)

Kalahari dwelling Damara mole-rats (Cryptomys damarensis) naturally fe ed on a high fibre diet of underground gemsbok cucumber tubers, Acanth osicyos naudinianus. We investigated the degree of fibre utilization a nd fermentation on this diet by measuring caecal characteristics (name ly temperature, pH and weight) and in vitro rates of gas and short cha in fatty acid (SCFA) production in these underground dwelling hind-gut fermenters. Rectal temperatures (33.8 +/- 0.6 degrees C) were consist ently higher than caecal temperatures (33.3 +/- 0.6 degrees C). Furthe rmore, a 0.8 degrees C gradient of temperatures existed within the cae cum, with the lowest temperature occurring in the corpus caeci. Both r ates of gas production (4.74 +/- 0.6 ml/g dry matter/hr) and SCFA prod uction (266.80 +/- 9.251 mu mol/caecum per hr) were high, with proport ionately more acetic acid produced than any other SCFA. Nevertheless, the initial concentrations of SCFAs present in the caecum were low (52 +/- 17 mM) implying a rapid rate of absorption of these SCFAs. The hi gh rates of fermentation provide a considerable amount of energy that would otherwise be trapped in fibre and thus unavailable to the animal . This highly efficient caecal fermentation enables the Damara mole-ra t to maximally exploit the underground food resources in the arid-zone ecotope.