Under a Confederate Moon — J.M. Snyder

Bitten as a teen, Caleb now suffers through a painful transformation from human to bobcat a few days each month. As a bobcat, he leaves behind his camp and fellow soldiers to explore the night. But a gunshot and the bright scent of fresh blood draws him to a clearing where he learns that he isn't the only one of his kind.

Wounded and hurt, Brance is a loner by nature, gruff and grumbling, who doesn't want anything to do with Caleb ... at first. The younger bobcat prevails, and starts to win Brance over, until they turn human again and find themselves on opposite sides of the American Civil War.