Yak taking a rest. Adapted to high altitude with larger lungs and hearts than normal cattle, they continue to produce foetal haemoglobin their whole life to increase oxygen carrying capacity. Conversely at low altitudes or above 15 degrees C (59 F) they begin to suffer from heat exhaustion due to a thick layer of subcutaneous fat combined with a lack of functioning sweat glands. Nepalese Himalaya. Nepal . Shot with Fuji Velvia slide film.
A Bennetts Wallaby (Macropus rufogriseus) with its thick winter coat in preparation for a snowy winter in Mount Field National Park which forms part of the Tasmanian Wilderness World Heritage Area. The predominately solitary and nocturnal creatures can occasionally gather together for food, water or shelter. The wallaby is sometimes known on the mainland as a Red-necked Wallaby however the Tasmanian form (Macropus rufogriseus rufogriseus) is predominately referred to as the Bennett's wallaby. It is much smaller and has dark thick long shaggy fur to deal with the harsher winters in contrast to the lighter thinner fur of its mainland relatives. Throughout nature it is common for island species to shrink in size relative to their continental cousins. Tasmania, Australia
A bighorn sheep (Ovis canadensis) in the twilight. The sheep roam in mixed herds of males and females in winter and segregated herds in summer. Jasper National Park, Alberta, Canada