While rarer among animals than in humans, monogamy is not uncommon. Around 90% of all birds form a monogamous relationship and sometimes mate for life. This behavior is attributed to the tedious courtship period involved in mate selection. Once a suitable pair bonds, they tend to stay together as they gain experience raising offspring with each mating period. Examples include the black vulture – where the entire flock will attack a single member if they display “cheating” behavior, and swans – who sometimes form bonds before sexual maturity and stay together throughout their lives.
Monogamy is seldom seen in other animals. About 5% of mammals, like Eurasian beavers, gibbons, and marmosets, form strong bonds with a single partner. Other than birds and mammals, hawksbill sea turtles, some seahorses, and even parasitic flatworms display monogamous behavior.