This is the location of the Tibetan Fox, above and to the left of the waterfalls near the top of the peak
The Tibetan Fox is an unlocked secret that is in the forest section, near the top of the peak, under the highest planted tree.
You can find it easily by selecting the Orange Fox, switching to camera mode, clicking the - symbol to go into free roam, then swinging the camera up to see the whole forest section and peak. Look above the Beavers and Capybara and left of the Ibex.
Click the Tibetan Fox and you'll get the achievement. You must unlock the Caniform first, then buy the Fox upgrade