Optimal foraging by a large ungulate in an extreme environment: Wild mountain reindeer select snow-free feeding habitats in winter.

Optimal foraging models predict that individual animals will optimize net energy gain by intensifying forage activity and/or reducing forage energy cost. Then, the free distribution model predicts an animal's distribution in a patchy landscape will match the distribution of the resources. If not modified by other factors, such patterns may be expected to be particularly explicit in variable and extreme, forage-limited, and patchy environments, notably alpine and Arctic environments during winter.

High winter loads of Oestrid larvae and are associated with emaciation in wild reindeer calves.

The Oestrid flies and and the nematode are important parasites of spp. The larvae of Oestrid flies develop in the throat () and skin () of their host during winter while develop in the CNS. Oestrid pupation, and development of larvae from first- (L1) to infective third- stage in the environment during summer are highly temperature dependent.

and infections in Norwegian wild reindeer and red deer populations in relation to summer pasture altitude and climate.

Nematodes of the genera and are associated with disease in semi-domesticated tundra reindeer and farmed red deer whereas less knowledge exists in the wild. Their first stage larvae (L1) develop to the infective third stage (L3) in the environment; spp. within intermediate gastropod hosts and spp.