Poem found on the May 5th Edition of "The Writer's Almanac"
This poem makes creates two comparative metaphors in which the focus changes from premise to action, and within that change two negatives exist.
The premise is first laid out in the first two lines, "During natural disasters two enemy animals / will call a truce." Theoretically, there doesn't need to be examples except for the first which is simple enough, "so during a hurricane / an owl will share a tree with a mouse." Here, we have the situation plus the two enemies able to coexist together.
But then the poem expands, not in existence or disparity in enemies, rather the actions the "predator" does. "during an earthquake, you might find / a mongoose wilted and shivering / beside a snake." and "The bear will sit down / in a river and ignore the passing salmon."
However, the comparison that stands out the most is the last one, "just as the lion will allow the zebra to walk home without comment." Here the turn has some anthropomorphism. Here, the lines signal a shift when the "predator" is allowing the "prey" to leave with no comment.
I wrote down that this poem is an action focused poem. Not in the sense of movement, but the subtle choice of verbs. "At funerals and weddings," is a big event, but when "the aunts who never speak nod / politely to one another." This little action shows a sense of coexistence -- note not kinship just like how "When my mother /was sick even the prickly neighbors / left flowers and cakes at our door."
It's not the intent, nor is it the grandiose scale of kindness --- just the action which the speaker states, "I love that there are exceptions."