The effect of forage structure and availability on food intake, biting rate, bite size and daily eating time of reindeer.
Factors influencing the food intake of reindeer (Rangifer tarandus tarandus) on tundra were studied using tame animals. Food intake was estimated from 2- to 5-min collections of oesophageal fistula egesta; biting rate was measured concurrently. Intake depended on plant sp., growth form and available plant biomass. When corrected to a constant biomass (50 g/m2) the ranking of eating rate was forbs > Salix spp. and Eriophorum vaginatum > Carex spp., Betula nana and lichens. Food intake increased linearly with standing crop for all growth forms except forbs which were eaten rapidly even when scarce. Prehension patterns were found to differ with plant growth form. A significant difference was found between bite rate and bite size when vascular plants and lichens were ingested. For Carex aquatilis and Eriophorum vaginatum a significant positive correlation was found between bite rate and food intake and a similar trend was noted for all vascular plants combined, but there was a negative trend between bite rate and food intake of lichens.