Some animals I met today, whose relations describe a continuum from kindly cooperation to deadly enmity

{Owen and Mzee, photographer unknown.}

From Pnin (1957), by Vladimir Nabokov

He seemed to be quite unexpectedly (for human despair seldom leads to great truths) on the verge of a simple solution of the universe but was interrupted by an urgent request. A squirrel under a tree had seen Pnin on the path. In one sinuous tendril-like movement, the intelligent animal climbed up to the brim of a drinking fountain and, as Pnin approached, thrust its oval face toward him with a rather coarse spluttering sound, its cheeks puffed out. Pnin understood and after some fumbling he found what had to be pressed for the necessary results. Eying him with contempt, the thirsty rodent forthwith began to sample the stocky sparkling pillar of water, and went on drinking for a considerable time. "She has fever, perhaps," thought Pnin, weeping quietly and freely, and all the time politely pressing the contraption down while trying not to meet the unpleasant eye fixed upon him. Its thirst quenched, the squirrel departed without the least sign of gratitude.

From The Executor: A Comedy of Letters (2006), by Michael Kruger, translated by John Hargraves

I caught a whiff of cigarette smoke and turned around to find her already standing in the room. Like an animal, I thought, that knows every hiding place in the apartment, can disappear at the first sign of danger, and reappears as soon as there's something it can grab and run off with. She must have lit her cigarette in her office, even though this was strictly forbidden, for the trip upstairs. She looked for an ashtray, and, not finding one, dropped the butt into a test tube--there were a couple of the desk, set in a wooden rack. She held her thumb over the opening until the glass took on a milky color and the butt went out. Then she put the tube back in its place.

From "Cat 'n' Mouse," by Steven Millhauser, collected in Dangerous Laughter (2008)

The mouse is sitting in his armchair with his chin in his hand, looking off into the distance with a melancholy expression. He is thoughtful by temperament, and he is distressed at the necessity of interrupting his meditations for the daily search for food. The search is wearying and absurd in itself, but is made unbearable be the presence of the brutish cat. The mouse's disdain for the cat is precise and abundant: he loathes the soft, heavy paws with their hidden hooks, the glinting teeth, the hot, fish-stinking breath. At the same time, he confesses to himself a secret admiration for the cat's coarse energy and simplicity. It appears that the cat has no other aim in life than to catch the mouse. Although the faculty of astonishment is not highly developed in the mouse, he is constantly astonished by the cat's unremitting enmity.

{Krazy and Ignatz, by George Herriman.}