Highest altitude sheep

The Biodiversity Heritage Library has this nice montage on its Facebook page, where it asks the question: “Which of the species pictured here lives at the highest altitude of all grazing herds?” You can vote here. I think the answer is the only non-wild sheep of the four, but it could be a trick question.

Brainfood: Species prioritization, In situ costs, Mycorrhiza, Crop diversity indicator, Diet diversity indicator, Ag & Nutrition, Chestnut blight, Oyster translocation, Maize introgression, Italian asses, New hosts for pests