a community of animals是复数概念，相当于a group of people, 所以用them指代。

burying them alive中alive并不是宾补，而是形容词作与宾语有关的状语，表示burying动作发生时宾语所处的状态。即burying them while they were still alive. When the mud buried them they were still alive.

Don't eat the egg raw. 不要吃生鸡蛋。= Don't eat the egg when they are raw.

形容词作状语，可能是与主语有关的状语，即形容词表示谓语动作发生时主语的状态；也可能是与宾语有关的状语，表示谓语动作发生时宾语的而状态。这是夸克《大全》中的观点。