Hunger
Hunger and the specifics of the act of eating which it produces has long been terrific fodder for metaphorical language. This is especially true in the use of similes where the comparison can make the connection to an elevated state of consumption clearer:
"She quickly rose up, lifted the container's lid, and gobbled down several of the small, crumbly lumps inside like a ravenous raccoon."
Animal Movement
The movement of animals is also a rich source for using similes. The ability to choose the perfect metaphorical imagery for comparison offers writers an effective tool for conveying an emotional state within the animal which may or may not actually be present:
"The bear moved slowly, arduously, as if every step was painful to it as it made its way down the slope into the closest valley. It seemed gout-sick or sounded in some way."
Sentience
Straight-up metaphor is engaged for the purpose of lending non-sentient objects the appearance of thought, motivation, and intent. Because so much of this story takes place outdoors in the natural world, this ability to give those aspects of nature an intelligence beyond their scope is especially effective:
"The rocks are strong, she thought, but the river wins. It turns. It tumbles. It chooses the path."
Swarming
Although hardly as common as other opportunities, there does seem to be a rich potential for using metaphorical imagery when something is swarming in a story. In this case as in others, swarming also offers the rare opportunity to reference locusts. They just don't make locust swarms like they used to:
"Far above her head, the footsteps of her swarming clan fell like shadows across the weaves of the sticks, like dark locusts flying across a reddened black sky."
Voices
Metaphor and simile are both equally useful for describing the peculiarities of speech. Things like inflection, volume, and the specifics of aural quality can all be made much more tangible with the addition of such imagery:
"...her grandmother rasped in the old language, her voice ragged and weak, so low that it sounded like the flow of a stream."
