The animal kingdom is full of different mating strategies both of terms of the physical ‘deed’ and courting/attracting mates. Mating is when a male and female of the same species (or genus) come together to reproduce and create offspring. In reality, ‘mating for life‘ is quite rare in the animal kingdom, but several species practice monogamy; providing exclusive mating rights to a single partner for a given period of time.
- Which animals mate for life?
Some animals are famous for their perceived monogamous behaviour: The European turtle dove (Streptopelia turtur) has been the subject of Shakespearean poetry for its dedication to its life partner. Turtle doves do indeed seem to pick a preferred mate, but they certainly aren’t as saintly as it first appears; females will commonly mate with passing males if they are deemed more desirable than their partner, this of course is done in secrecy when their partner is away feeding. Similarly, mute swans (Cygnus olor) are also almost a mascot for romance and love, especially in Western popular culture, and although they are very likely to stick with a single partner for most of their life, they are able to find new partners if their first partner dies.
- Do all birds mate for life?
Well no, but around 90% of all bird species practice some variety of monogamy, however, there is a lot a variation within that. Emperor penguins (Aptenodytes forsteri) for example have a mating system called ‘serial monogamy‘. These penguins famously go to great lengths to work together as parents to raise a single chick in the hospitable ice fields of Antarctica but once that chick is grown, the couple part ways and might never meet again. Emperor penguins pick new mates every breeding season and although they are fiercely loyal to their partner during their relationship, their affair won’t last into the next year.
Some birds have social standards when it comes to being faithful to their partners; such as black vultures (Coragyps atratus) who form strong partner bonds but are never the less still tempted to cheat on their partners. If other members of a group black vultures catches an individual mating with someone other than their partner, then the group will attack them! Adultery is a punishable offence for these birds. Similarly, male blue-footed boobies (Sula nebouxii) will react dramatically to a cheating partner; males will roll eggs out of the nest if they doubt their paternity, prompting females to be more faithful or else they may lose their offspring.
Bald eagles (Haliaeetus leucocephalus) are noted for their dedication to a partner, often spending as long as 35 years living together. In order to form a bond, the eagles engage in spectacular flight displays and trust exercises, for example, they will soar high into the sky, inter-lock their talons (feet) and free-fall, only separating just above the ground. Once they find their ideal partners, a couple of bald eagles build a nest together and build upon it every year as they raise several chicks. A lifetime of building a home together can result in spectacular nests, the largest tree nests of any bird in fact; one nest in Florida, U.S.A. was 6 metres deep and weighed nearly 3 tons! However, even these birds don’t have perfect relationships; they will break up if they are unable to produce offspring after a few seasonal attempts.
The outright champions of commitment to partners (other than humans of course) have to be albatrosses (family: Diomedeidae). We’ve mentioned these interesting sea birds before, but they are extremely fascinating when it comes to their monogamous mating behaviour. Like bald eagles, albatrosses engage in mating displays but there’s take place on the ground and involve elaborate dances with their prospective partners. Once a partner is selected they will spend the rest of their lives producing offspring exclusively with each other. As of yet, we don’t even know for how long an albatross can live, we haven’t been recording them for long enough, however, so far it has been observed that an albatross partnership can last for at least as long as 50 years, each year, the partners meet up at the same place to mate and raise their chicks. It takes an albatross many years to perfect the art of dancing, sometimes they won’t be able to secure a mate for 15 years, so this may explain why they are reluctant to split up, given the effort it took to form the relationship in the first place! Even when an albatross loses its mate, it may not seek out a new one for several years; perhaps they are mourning?
In the next post, we will look at some of the other animals that practice monogamy. Although birds are the most faithful to their mating partners, there are other animals that adopt similar practices.