Sexual dimorphism: several interesting examples of differences between the sexes in nature (7 photos)

In nature, there are such strong differences between the sexes that carriers of different sets of sex chromosomes can be mistaken for separate species.





Sexual dimorphism is a scary thing. For us people, it is extremely moderate, but this is enough to endlessly argue about rights, responsibilities and position in society.



The invited guests of this article are peacocks. Their difference between the sexes works on a simple principle. The female looks at this overdressed male and thinks: “Wow, did it survive? This means our children will be just as resilient!” By the way, the average life expectancy of male peacocks is 2 times lower than that of females.

Look at the picture below. Would you mistake these two parrots for the same species? So ornithologists who studied the avifauna of the tropical forests of Indonesia left notes in which they clearly indicated that they met two different species of parrots. Only further (and rather lengthy!) observation showed that this is a noble red-green parrot, whose sexual dimorphism has reached the extreme. Moreover, the females of these parrots are bright and red, and the males are only modest green laborers. Usually in birds it's the other way around.



This gap in appearance is associated with unusual mating games. The entire life of females revolves around nesting sites. Once she finds a comfortable hollow, she will spend up to 11 months of the year there! Only there are a lot of ladies, so comfortable places are always in short supply. If a girl leaves, a competitor will immediately take her place. To play it safe, parrots do their best to attract the attention of males: with bright colors and seductive cries. One female can be courted by up to 5 gentlemen, ready to feed and deify their lady of the heart. However, the boys are also not bad, each of them gives attention to several beauties at once.



Where are the goodies??? You are losing my favor!

There are differences that are even more radical. Look at spiders: their females are almost always larger than their males. But among the nephilic orb weavers the difference is greater than among any others. Representatives of the fair half of these tropical spiders are quite large: the span of their legs reaches 13 centimeters, and their body length is 5 centimeters. But the males are 10 times smaller, they are real babies!



A female surrounded by her harem

This sexual dimorphism allowed the species to maximize offspring production and reduce associated costs. Small males eat little and are very inconspicuous, so they are able to travel long distances without much risk to themselves. Whereas large females are able to lay many eggs and catch large, tasty insects. Fortunately, the fishing net allows it; the nephils have one of the strongest nets on the planet!



After mating, the male remains close to the female and protects her from the attacks of other men.

But even the difference between spider sexes is just a joke compared to the sexual parasitism of anglerfish. Their females are eerie fish with huge, toothy mouths and fishing rods whose tips glow deathly pale. And the males are small, fry-like fish that bite into the female’s flesh and feed on her blood, giving in return the opportunity to continue their race. Anglerfish were discovered in 1833, but only a century later people realized that it was not parasitic fish hanging on the bodies of females, but males.



You are so beautiful that I can’t tear myself away from you!

This strange difference between the sexes arose due to strict necessity. Anglerfish live at enormous depths, from 600 meters below sea level. There, in the eternal darkness, it is very difficult to find each other. Keeping in flocks is not an option: you will scare away all the food. So the males found a way to maintain close contact with the female, but at the same time almost not deprive her of nutrients. One lady can maintain contact with 3 males at once!