I'd like to make an exhaustive list of the various animals whose milk humans drink. Here's the ones I can think of:   human cow goat sheep camel yak buffalo donkey/ass   Any others? If so, where? 
Add to this answer...  Who and where, what it tastes like, how it differs, how it's used in cooking...  Human  Where: Worldwide    Uses: Nursing  Cow  Where: Most common source of dairy worldwide    Uses: All dairy products (milk, cheese, yogurt, etc.)  Goat  Where: India, Bangladesh, Africa, France, common across Europe.    Uses: Milk, cheese  Sheep  Where: Across Europe    Uses: Primarily cheese  Camel  Where: Middle East    Uses: Milk  Note: Camel milk can be an important source of water in extremely arid climates or survival situations.  The milk can have a salty taste due to camels' high consumption of sodium.  Yak  Where: South East Asia, Mongolia, Northern China, Tibet, Nepal   Uses: Milk, Cheese, and butter; localized dairy products such as dahi, paneer  Water Buffalo  Where: India, Parts of the Middle East, Southeast Asia, China, South America, Europe (best known in Italy and throughout the Balkan states)  Uses: Milk, yogurt, cheese (mozzarella and others), candy  Note: Water Buffalos are the 2nd most common source of dairy in the world.  Horse  Where: Mongolia  Uses: Kumis (lightly alcoholic fermented drink)  Donkey / Ass  Where: Mediterranean countries    Uses: Milk, yogurt, cosmetic and medical use  Reindeer / Caribou  Where: Scandinavian countries, Mongolia  Uses: Cheese, Butter  Note: Reindeer milk is 22% butterfat and produces extremely rich cream cheese which Lapplanders sometimes use in coffee rather than regular cream.    Moose  Where: Russia and Sweden    Uses: Milk, limited cheese production 