As Henry Reich explains in this installment of Minute Earth, yes, monogamy does exist in the animal kingdom – though fewer creatures practice it than you probably realize.
Monogamy is observed in just over a quarter of primates and only around 3–5% of mammals, overall. How it evolved in humans is still the subject of intense debate, and with good reason. "Monogamy is a problem," University of Cambridge zoologist Dieter Lukas once put it. "Why should the male keep to one female?"