SAN DIEGO—According to a University of California–San Diego study released Monday, sexism is rampant throughout the natural world, particularly among the highest classes of vertebrates.

One of the millions of lionesses trapped in an abusive relationship.

"When we first decided to examine attitudes and behaviors toward gender roles among non-humans, we were wholly unprepared for what we would find," said Jennifer Tannen, leader of the UCSD research team, a joint venture between the school's zoology and women's studies departments. "Females living in the wild routinely fall victim to everything from stereotyping to exclusion from pack activities to sexual harassment."

Nowhere is the natural world's gender inequity more transparent, Tannen said, than in the unfair burden females assume for the rearing of offspring.

"Take the behavior of the ring-neck pheasant," Tannen said. "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. Nor is there any legal recourse. It's despicable."

Tannen said pheasants are typical of the natural world, where a mere 5 percent of animal species mate for life. Among species that do form lasting pairs, the situation barely improves: Females must remain close to the nest to incubate eggs, nurse, and keep watch over the burrow while males are free to go off hunting and fishing with their friends.

"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," Tannen said. "Sadly, most creatures never pause to challenge these woefully outdated gender roles."

Tannen stressed the need to hold high those rare examples of species that do form caring, mutually supportive relationships.

"Wolves, beavers, gibbons, and a small African antelope known as a dik-dik all live in stable, monogamous pairs," Tannen said. "Other animals need to look to them as positive models if we are to have any hope of one day creating an ecosystem of understanding and respect."

More seriously, in addition to an unfair division of labor, nature is rife with sexual abuse and harassment. The UCSD study estimates that in 2001 alone, more than 170 trillion cases of abuse occurred in the world's forests, grasslands, and oceans—all of them unreported.

"During the act of mating, the female moose is subject to excessive biting, nipping, and herding," Tannen said. "The male has no qualms about using sheer, brute force to overpower his sex partner, and the female, accustomed to this sort of rough treatment after millions of years of it, doesn't even realize there's something wrong."

"Then, when it's time for the bull moose to complete the sexual act," Tannen continued, "it's over in about five seconds, with no regard to female pleasure whatsoever. Typical."

Adding insult to injury, Tannen said, the bull moose then heads off to mate with dozens more females over a period of two to three weeks, justifying his behavior as "part of the Mardi Gras-like atmosphere of 'mating season.'"

With other species, darker situations unfold.

"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," Tannen says. "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."

A cock reinforces the poultry world's sexist, male-dominated social hierarchy.

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

"We've all heard the lurid tales about the female black-widow spider, who kills and eats her mate," Tannen said. "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. But no one condemns the male for his part in this destructive relationship."

UCSD researchers identified 24 distinct male behaviors designed to perpetuate gender inequity and preserve the prevailing power structure. Among these dominance-asserting behaviors are chest-puffing, plumage-spreading, and antler growth.

The UCSD study is not without its detractors. Glen Otis Brown, author of Forced To Strut: Reverse Sexism In The Animal World, countered that male animals are victims of "the beauty myth" as much as females.

"When given a choice, female green tree frogs gravitate toward males that call the loudest and most often," Brown said. "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."

Tannen conceded that both genders have suffered as a result of sexism.

"Other than sexual size dimorphism due to same-sex competition, males benefit little from the gender inequity that so strongly favors them," Tannen said. "In a world where interactions are rooted in competition, not cooperation, both females and males are being denied the right to form meaningful relationships."

Annie Secunda, a Boston-based females'-rights advocate, said swift action must be taken to address the problem of sexism within the animal kingdom.

"We need to provide tigresses, hens, and all other females in nature with outreach programs and support networks," Secunda said. "We also need to impose standards through intervention. The males of all species need to hear loud and clear the message that this kind of animal behavior is not acceptable."

Secunda conducts numerous workshops aimed at creating female-friendly biomes and promoting the health and positive self-image of females on both land and in the sea. She also strongly advocates the legalization of infanticide, which would enable females to devour their newborn offspring when resources are limited.

Secunda spent much of 2001 in the Amazon rainforest, working to create safe spaces for female animals. These efforts, however, yielded mixed results: Females have avoided the lighted walkways she built in several dangerously dense areas, and leaflets encouraging females to learn how their own bodies work were ultimately used to line dens for the rainy season.

Far from discouraged, Secunda said she plans to embark on an intensive study of the sexuality of flora.

"Multicellular plants alternate sexually reproducing and asexually reproducing generations, with each plant producing both male and female gametes," Secunda said. "It seems many plants have moved past conventional notions of male-female gender altogether. It's so liberating, I can't help but have hope for all those so-called 'higher' species of animals."