For many of us, marriage is special. The idea of a lifelong bond between two people is accorded legal, spiritual and cultural significance throughout much of the world. Whether we are religious or secular, a permanent monogamous relationship can feel sacred.
So when we hear about animals that form lifelong bonds, our "aww" factor goes into overdrive: "How adorable! Gosh, we could all learn a thing or two from those shingleback lizards".
But for all the romantic novels, love songs and soppy greetings cards, monogamy remains more of an ideal than a reality.