Tuesday, February 14, 2017

Which animals mate for life? As it turns out, very few

So here is my first ever (and probably last) Valentine-themed post. I happened to catch part of a radio program about monogamous animals, ones that mate for life and that typically remain faithful till death them do part (so to speak).
Given that the divorce rate among humans is now over 50% in many developed countries (e.g. 47% in UK, 48% in Canada, 53% in USA, 61% in Spain, 67% in Hungary, 71% in Belgium), although much less than that in many more traditional or religious countries, it is debatable whether humans qualify for that designation. But in the animal kingdom the following are generally considered monogamous:
  • Prairie voles - unlike most rodents, male prairie voles are fiercely monogamous and may even attack other females that try to approach them, although they do occasionally stray and mate with strangers, for no apparent reason.
  • Eurasian beavers - beavers that have been reintroduced into Europe are typically monogamous, while the more common and less aggressive North American beavers are most definitely not.
  • Gibbons - the closest monogamous relative to humans, gibbons are mainly monogamous over their 35-40 year life, although around one in ten of a female's babies maybe from a different "opportunistic" partner.
  • Azara's night monkeys - studies have shown that these South American monkeys are entirely monogamous, and the males provide a large amount of parental care.
  • Wolves - the pairing of the alpha male and alpha female establishes the social structure of the pack, which is not dissimilar to the nuclear family of humans (although a family unit can number up to 20).
  • Kirk's dik-dik - dik-diks (and a few other African dwarf antelope species) establish permanent pair bonds, although the males do not help with the rearing of young.
  • Otters - some species of otters (including giant river otters) live, travel, sleep, play and hunt together in pairs and family groups, while others (including sea otters) don't.
  • Black vultures - vultures share incubation and feeding duties equally, and other vultures in the area have been known to attack philanderers who are tempted to stray from their monogamous bond.
  • Bald eagles - tend to spend the winters and migrations seasons alone, but the male always returns to the same nest and partner each year during the mating season, and helps out with the eggs and fledglings.
  • Barn owls - mainly remain faithful to one mate, unlike most birds (which are generally "socially monogamous" rather than "genetically monogamous"), and even cuddle and show affection to each other.
  • Golden eagles - usually monogamous, and pairs may remain together for several years or even for life.
  • Condors - like a few other large birds of prey, condors mate for life (and they can live anywhere from 50 to 100 years).
  • Penguins - many species, like Emperor, Royal and African penguins, stay together while the chick is raised, although they then usually split up.
  • Swans - pair bonds in swans last for many years, and often for life, and the male also helps to incubate the eggs and watch over fledglings.
  • Albatrosses - although they spend most of the year on the wing over the ocean, albatrosses always return to the same island to mate (and dance) with the same partner.
  • Mourning (turtle) doves - this common North American bird is mainly monogamous and both parents incubate and care for the young.
  • Sandhill cranes - these social birds live together in pairs of family groups throughout the year, and both parents hep incubate the eggs and care for the young.
  • Termites - unlike with ants or bees, the queens of some species of termites form lifelong bonds with a "king", and the two engender the entire termite kingdom.
  • Shingleback skinks - one of the few reptiles known to mate for life, these Australian skinks actually spend much of the year on their own, but always return to the same mate in the mating season.
  • Red-backed salamanders - they are at least socially monogamous, and will maintain co-defended territories.
  • French angelfish - these aggressive fighting fish live, travel and even hunt in lifelong pairs, and both partners vigorously defend their territory.
  • Pot-bellied seahorses - given that the male carries the babies (as with all seahorses), the females of this large Australian seahorse species vie for the attention of the males, unlike in most of nature.
  • Schistosoma mansoni worms - a parasitic flatworm found in humans (and responsible for the disease schistosomiasis or "snail fever"), they reproduce within the human body and form loyal monogamous pair bonds, and go on to produce about 300 eggs per day.
This list, compiled from various internet sources, shows that those animals that are wholly or mainly monogamous make up a tiny and seemingly random selection in an overwhelmingly promiscuous natural world.

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