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The　ｌｉｓｔｅｎｉｎｇ　ｍａｔｅｒｉａｌ　ｆｏｒ　ｔｈｉｓ　ｐａｒｔ：

Geladas are very peaceful monkeys. In the cold it's a waste of valuable energy to quarrel. So instead, they've developed more subtle ways to signal their mood. In gelada society, disputes are usually settled by just pulling a face. But each band of geladas has up to thirty dominant males, and tensions do sometimes boil over.

In the last million years, Ethiopia has been much colder than it is today. Glaciers once crowned these highlands, carving the brittle rock into a landscape of jagged spires, some falling two kilometres to the base. Geladas are fearless rock climbers. Each evening, they move to the steepest cliffs for safety from predators like leopards. While gelada baboons have always lived in this region of Africa, it's only with time that they've been able to move up in the world.

But Ethiopia hides many other unusual mountaineers and some have colonized these peaks from much further afield.

Walia ibex invaded Africa from Europe during recent Ice Ages when the two continents were joined by a vast tundra. Today these rare goats survive only on the remotest pinnacles. In the breeding season, the cliffs echo to the sound of males contesting dominance. These fights can be brutal and occasionally to the death. Ethiopian Thick-billed Ravens are quick to take advantage.

brittle adj. Likely to break, snap, or crack, as when subjected to pressure:

易碎的：如受压后可能打碎、断裂或打破的
jagged adj. 粗糙的, 凸凹不平的 afield adj. Off the usual or desired track

偏离地：偏离惯常或预期的

tundra n.  A treeless area between the icecap and the tree line of Arctic regions, having a permanently frozen subsoil and supporting low-growing vegetation such as lichens, mosses, and stunted shrubs.

苔原：北极地区冰盖和乔本植被线之间的无树地区，有永冻底土，并支撑低的植物，如苔藓、地衣和发育不全的灌木

pinnacle n. A tall, pointed formation, such as a mountain peak.

高峰，山峰：高而尖的结构，如山的顶峰

Thick-billed Ravens n.