Not only human males are "pigs" and "jerks" and not only women are "bitches". A recent research made at University of California-San Diego shows sexism is rampant throughout the natural world, especially amongst vertebrates. "Females living in the wild routinely fall victim to everything from stereotyping to exclusion from pack activities to sexual harassment," said lead researcher Jennifer Tannen.

"Nowhere is the natural world's gender inequity more transparent, than in the unfair burden females assume for the rearing of offspring. Take the behavior of the ring-neck pheasant (we should add, of all pheasants and related species). After mating, the male immediately abandons the hen, leaving her responsible for the total care for the chicks. For the single mother-to-be, there is no assistance, either in the form of a partner or child support. Pheasants are typical of the natural world," said Tannen.

She omits to signal the reverse: the polyandria, when only the male takes care of the eggs and the offspring, like in nandu, some shore birds or buttonquails.

About 5 % of animal species mate for life (form monogamous pairs).

Tannen says the situation barely improves: females must stay close to the nest to incubate eggs, nurse, and keep watch over the burrow while the males are free to go off hunting and fishing with their friends. This is not very precise: many monogamous males do incubate, and many stay and protect the nest and the offspring when the female is off. "The sexist attitude that child-rearing is 'women's work' is prevalent throughout nature and has been for generations, probably since reptiles first developed mammalian characteristics in the Triassic period," said Tannen.

"Wolves, beavers, gibbons, and a small African antelope known as a dik-dik all live in stable, monogamous pairs," said Tannen, and also many bird species, from penguins, albatrosses and storks to little song birds.

The study points out the cases of sexual abuse and harassment in nature: in 2001 alone, over 170 trillion cases of abuse occurred in the world's forests, grasslands, and oceans. "During the act of mating, the female moose is subject to excessive biting, nipping, and herding. The male has no qualms about using sheer, brute force to overpower his sex partner," said Tannen.

"Then, when it's time for the bull moose to complete the sexual act it's over in about five seconds, with no regard to female pleasure whatsoever. Typical. Adding insult to injury, the bull moose then heads off to mate with dozens more females over a period of two to three weeks, as part of the Mardi Gras-like atmosphere of 'mating season."

Still, for Tannen, this type of polygamy is soft: "To mate, the male Galapagos tortoise simply immobilizes the female with his weight, which, as far as I'm concerned, qualifies as non-consensual sex. Female southern elephant seals gather in large groups during mating season, and each group has a small handful of males who control them like a harem. It's sick." said Tanne.

"When female animals refuse to play along with prescribed gender roles, they are demonized. For example, female foxes, known throughout the animal kingdom for their aggressiveness, are labeled "vixen."" said Tannen.

She should have learned that genetic analysis showed that vixen are promiscuous and in many cases the male brings to the den food for cubes that are not fathered by him. "We've all heard the lurid tales about the female black-widow spider, who kills and eats her mate. The truth is, male spiders encourage their partners to kill them because it increases the time spent mating and, thus, the number of eggs fertilized by his sperm," said Tannen.

This is really an interesting point of view. What about the jacana females that smash the eggs of their female rivals, just to make the males incubate and take care of their own eggs/chicks?

The team detected 24 distinct male issues aimed to maintain sexual inequity, from dominance-asserting behaviors are chest-puffing, plumage-spreading, to antler growth.

Some have counteracted the feminism applied to the animal world. "When given a choice, female green tree frogs gravitate toward males that call the loudest and most often. Female Poecilia reticulata [guppies] go straight to the most brightly colored males. But when males evolve exaggerated secondary sexual traits to attract the opposite sex, suddenly they're the bad guys." replied Glen Otis Brown, author of Forced To Strut: Reverse Sexism In The Animal World, showing that both males and females are victims of "the beauty myth".
Tannen even admits it. "Other than sexual size dimorphism due to same-sex competition, males benefit little from the gender inequity that so strongly favors them."

Because indeed, the peacock's large tail or the deer's large antlers are rather a burden in the struggle for survival.