Mort(e), by Robert Repino

The apocalypse is upon us, and it is cute and fluffy. After millennia of mistreatment, the ants have had enough. Systematically gathering knowledge and information to herself, the Queen sets in motion a plan to end the scourge of humanity. To help in her dark endeavor, she releases a hormone into the water supply that turns all animals into sentient beings, makes them human-sized, and gives them opposable thumbs. Pets rise up and kill their masters as armies of enormous ants rip any human they find to shreds. Sebastian, a neutered house cat, has recently found happiness and friendship with his neighbor's dog, Sheba. But upon the uprising, Sheba has run away and Sebastian, now known as Mort(e), is left to wander a broken world, forever looking for her. As the animals battle a bioengineered disease known as EMSAH and hunt down the last remaining humans, Mort(e) wraps himself in loneliness, wanting only his old friend with whom to share his new life.

This is a pretty action-packed book, and would make a killer movie. It reads quickly and easily, while presenting some interesting deeper themes - religion, the afterlife, whether there is such a thing as munificent domination. It reminds me of The Bees, in its description of the ants. It's a great book for anyone looking for a slightly different kind of apocalypse page-turner.