Sure, the birds do it, and the bees do it, but do any animals go beyond procreation and stick together for life? Of the more than 63,000 vertebrate animal species in the world, monogamous relationships occur in just a small fraction. That tiny percentage includes the well-publicized faithful penguins and trumpeter swans, but also some creatures that are less cute and cuddly. Here are five examples from around the animal world that you may not know about.
Unlike recent French presidents, French angelfish tend to stick with one partner for life. The reef-dwellers live, travel and even hunt in pairs. The fish form monogamous bonds that last until death does them part. In fact, they act as a team to vigorously defend their territory against neighboring pairs. Researchers say that the fish probably practice monogamy because they have many predators in the reef, and sticking together as a team increases the probability that their offspring will survive.
Unlike their coyote cousins, gray wolves form monogamous bonds and form a nuclear family unit a male, female, and their offspring. The pact is solid, in the wild, until one of the wolves dies and the remaining wolf quickly finds another partner. In captivity, wolves have been observed acting in a polygamous way probably because of stress caused by their surroundings. Wolves are possessive, act with jealousy, and attempt to prevent other members of their pack from establishing similar bonds with their mates.
Black vultures not only practice social monogamy, where both parents hunt and raise a family together, but also sexual monogamy. One recent study analyzed vulture DNA to check if any dalliances were happening outside of a pair's bond, and found that the vultures were indeed strictly faithful. Even after the death of one half of the pair, the other will not seek out a new partner and vultures have been observed attacking other vultures who stray from their mates.
Sure, these worms are the parasite that causes the chronic illness schistosomiasis, but they're also a beautiful love story. When the male and female meet, the female climbs inside him and lives in a groove in the male's body where they mate and raise baby parasites. The reasons for this quirk of parasitic monogamy are complex; the worms exist in an ancestral evolutionary state somewhere between hermaphroditism and polygamy.
Gibbons are the closest cousin to humans that are monogamous at least, close to it. The apes defend their territory by singing duets and chasing away members of their own sex. Males and females are roughly the same size, and lone gibbons are rarely seen. Scientists used to believe that they were completely monogamous, but now have observed instances of "divorce" and mate-switching. Still, gibbons are socially monogamous and raise young together as a unit.