In Montana, guide Erin Bolster, 26, was leading a group of eight tenderfeet on a horseback ride when a grizzly bear suddenly charged an eight-year-old boy. Bolster got her horse, Tonk, between the boy and the bear (an extraordinary feat, since horses are naturally bear shy), and then horse and rider charged the grizzly several times, eventually scaring off the critter and saving the child. Now that’s what we’re talkin’ about. 

Image courtesy of Christen Rak

In The Buddha in the Attic, Julie Otsuka, 50, writes of early-20th-century Japanese women who were imported to the U.S. to marry their countrymen, who couldn’t legally marry whites. Her novel, restrained but gorgeous, illuminates the lives of immigrants in a culture that baffles and buffets them. 

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Brilliant, breakout, career making, game changing, sidesplitting—the Oscar-nominated performance of Melissa McCarthy, 41, as the magisterially nuts Megan in the comedy Bridesmaids threatens to deplete the world’s laudatory-adjective supply.

She feels fiercest when: “I walk into my house and I’m tackled by my kids. That kind of love is empowering.” What she finds unforgivable: “Front-pleated khakis. Come on, people.”

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Kristen Wiig, 38, delivered a nuttily nuanced performance in Bridesmaids and cowrote the Oscar-nominated screenplay. She also proved that a female ensemble can score box office gold; the film earned nearly $300 mil­lion worldwide—more than its producer, Judd Apatow, made with testosteronic blockbusters like Knocked Up—and set a record as the most popular video-on-demand movie ever. And although Apatow insisted on inserting a poop ’n’ puke scene, Wiig stood firm on getting female friendship right. 

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Canned by Yahoo in September 2011, former CEO Carol Bartz, 63, didn’t go quietly. “These people f___ed me over,” she told Fortune. Though she cut costs and improved profit margins, the board felt she didn’t grow revenue fast enough. (She claims she would have by 2012.) Public venting may have been satisfying, but it’s likely to cost Bartz about $10 million—she had a nondisparagement clause attached to her golden parachute. “I am beyond grateful that I have the ability to stand up for my beliefs,” Bartz tells us, “and I have no regrets when it comes to speaking my mind.”

She feels fiercest when: “People twist facts to support their opinions. One of my favorite sayings is ‘You’re entitled to your own opinion, but you’re not entitled to your own facts.’”

Her mantra: “‘Fail, fast, forward.’ In other words, don’t be afraid to fail, try to recognize failure quickly and use it to move forward.” 

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Seriously, Bank of America? You really thought it was a good idea to charge customers $5 a month to use their debit cards? You didn’t count on mad-as-hell Kristen Christian, 28, of Los Angeles, who successfully fought the fee, rallying thousands of Americans via Facebook to protest by closing their Bank of America accounts.

What she finds unforgivable: “The inability to forgive—ourselves and others. Human beings are imperfect.” B of A, breathe a sigh of relief.

Image courtesy of Max S. Gerber

Mexican journalist Lydia Cacho Ribeiro, 49, uncovers crimes against women and children. Her work—most recently a series about women murdered in Ciudad Juarez—elicits death threats. That’s more than rhetoric in Mex­ico, where the mortality rate among the media is eighth worldwide.

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Among the mostly male rescuers of the world’s whacked-out finances, two women stand out: Christine Lagarde, 56, formidable former French finance minister, is the first woman to head the International Monetary Fund, succeeding Dominique Strauss-Kahn (relieved of his duties after being accused of sexual assault). In her youth, the nearly six-foot Lagarde was a member of France’s national synchronized swimming team. Maybe that’s helping her keep the global economy afloat. 

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Wangari Maathai, the first African woman and the first environmentalist to win the Nobel Peace Prize (in 2004), died last year at 71. An activist in Kenya, she started the Green Belt Movement, organizing women to rally for free elections and to fight deforestation with new trees. They eventually planted 40 million throughout Africa. In 2006 she joined forces with the U.N. to launch the international Billion Tree Campaign—and since then more than a billion trees have been planted worldwide each year. 

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Don’t mess with Missouri bond broker and single mom Lucy Nobbe, 52. Enraged by Congress’s inability to work productively and by Standard & Poor’s first-ever downgrade of America’s credit rating, she hired a plane to fly over S&P’s Wall Street headquarters trailing a banner that read "Thanks for the downgrade... you should all be fired!" 

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Three million subscribers eagerly await the daily flash sales and deliciously curated collections of One Kings Lane, the online shopping paradise for home decor cofounded three years ago by Susan Feldman, 56, and Alison Pincus, 37. In 2011 their formula—high-toned house porn at a deep discount, so invitingly staged that virtual decorating feels totally unrisky—generated $100 million in revenue. 

Image courtesy of Susan Feldman

After designer Alexander McQueen committed suicide in 2010, in-house star Sarah Burton, 37, was promoted to creative director. Triumph soon followed: She designed the world’s most famous wedding dress (no, not Kim Kardashian’s—Kate Middleton’s). Burton is also responsible for turning royal sis-in-law Pippa’s satin-crepe-encased bum into a global meme. 

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As a friend of Kathryn Stockett, author of The Help, actress Octavia Spencer, 40, inspired the character of Minny, the maid in the ’60s segregated South who proves that revenge is a dish best served in a pie tin, spiked with the unspeakable. We love Spencer’s combination of playfulness and substance, attitude and gravitas—all of which earned her an Oscar for Best Supporting Actress.

The hardest part of being fierce: “When it is misperceived as blind ambition.”

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How’d she pack so much menace and longing, power and pathos into that teeny little illustrated and perforated bod? Kudos to Oscar nominee Rooney Mara, 27, for bringing The Girl with the Dragon Tattoo to life with equal parts ferocity and vulnerability.

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In 2008, when Sue Falsone, a physical therapist for the Los Angeles Dodgers, became the first woman trainer in major league baseball, a player gave her a fielder’s glove embossed with the acronym FWTMLB. Now she needs a new glove: Last year Falsone, 38, was promoted again, and now is the first woman in the history of major U.S. professional sports to become a team’s head trainer. 

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Gynecologist to the Thai royal family, Kobchitt Limpaphayom, MD, 71, campaigned to introduce a simple screening method for cervical cancer—and to allow nurses, not just doctors, to perform the procedure. She’s helped save thousands of lives, especially among rural women.

She feels fiercest when: “I discover that someone has cheated my patients. When a woman dies for lack of available health services, she has been cheated.”

Image courtesy of Kobchitt Limpaphayom

Last year, as Catherine Zeta-Jones, 42, supported husband Michael Douglas in his fight against cancer, she was fighting a battle of her own: The Oscar-­winning actress sought treatment for bipolar disorder. Her courage in being open about her illness helped demystify a problem that affects nearly six million Americans. Zeta-Jones is now happily back at work, earning great buzz for her role as a Las Vegas gambler’s wife in Lay the Favorite, out this summer. Her three good reasons to be fierce: Husband Michael and kids Dylan and Carys. 

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Separated from her camera crew during the Egyptian revolution, journalist Lara Logan, 41, was sexually assaulted by a mob of angry men. She dared to discuss the experience on 60 Minutes—and her account has had an effect. According to Women Under Siege, a project of the Women’s Media Center spearheaded by Gloria Steinem, Logan has inspired more women journalists to come forward to report sexual violence. 

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We salute the cast of Desperate Housewives, wrapping its eighth and final season. So long, Lynette; bye-bye, Bree; adios, Gabrielle; see ya, Susan. Au revoir, husbands and lovers—surviving, departed and dispatched. Go with God, Mary Alice, world’s chattiest corpse. In good times and bad, these women’s default positions were forgiveness and solidarity. The foundational ladies of the lane, embodied by Felicity Huffman, 49, Marcia Cross, 50, Eva Longoria, 37, and Teri Hatcher, 47, always had one another’s backs. Sisters before misters, yo!

The hardest part of being fierce is: “ . . . being willing not to please others. As any pleaser knows, that is no small feat.” —Marcia Cross 

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They've got game. Last year, Pat Summitt, 59—the coach of the University of Tennessee’s women’s basketball team and the winningest college coach in history for either sex—was diagnosed with early-onset Alzheimer’s disease. True to her fighting spirit, she went public with her condition and continued coaching. In April she stepped down from the job she had held for 38 seasons, taking the title of head coach emeritus. She says she will "continue my active role as a spokesperson in the fight against Alzheimer's through the Pat Summitt Foundation Fund."  She has also signed a contract to write a book (with Washington Post columnist Sally Jenkins as co-author) chronicling her life and career. "Basketball has always been far more than a game to me," Summitt said. "It's a way of being, an ethic and a value, and so my intention is that this will be more than a sports book." 

Her motto: “Don’t let anyone outwork you!” 

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What's the most fabulously ferocious thing about Adele, the gorgeous 24-year-old Cockney contralto with a vast voice, an old soul and eight Grammys, including one for Album of the Year? Is it the way she’s rebounded from scary throat surgery? The fearless vulnerability in the songs she writes, transmuting heartbreak into art? The metaphorical middle finger she flipped at designer Karl Lagerfeld when he declared her “a little too fat”? (Her response: “I’ve never wanted to look like models on the cover of magazines. I represent the majority of women, and I’m very proud of that.”) The actual finger she cheerfully gave at the British music awards when the host cut her off during her acceptance speech? It all adds up to a young’un fierce enough to remain relentlessly herself. 

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Seattle student Amanda Knox, 24, spent four years in an Italian prison for murdering her roommate before that decision was reversed last year. She owes her freedom to the discrediting of evidence used to convict her—and to the fortitude of her mother, Edda Mellas. The 49-year-old math teacher fought unflaggingly for Knox’s release, renting a house in Italy so she could be on hand for various steps of the legal process. And she raised money—by tapping out her retirement funds and going into debt— so that she, along with her ex-husband, Knox’s father, could pay more than $1 million in legal fees. (Knox’s February book deal for nearly $4 million should help.)  

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Not that it ever mattered to her, but Gloria Steinem is still glamorous at 78. Last year she celebrated the 40th anniversary of the founding of Ms.—amazingly, the first American magazine written, edited and published by women for women. On the page, at marches, in policy debates, Steinem changed laws and lives. Just one of the glorious Glo-quotes we’ll be needlepointing on pillows (but only if we want to!) for generations: “A liberated woman is one who has sex before marriage and a job after.” 

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Great moments in oh-no-he-didn’t: A cop addressing students at Toronto’s York University in 2011 suggested that “women should avoid dressing like sluts” in order to be safe on the streets. He later apologized—but not before feminists Heather Jarvis (left), 26, and Sonya Barnett, 39, had organized the inaugural SlutWalk, the first in a series of nearly 200 powerful marches worldwide, protesting the blaming of victims and declaring it a woman’s right to be safe from assault no matter what she’s wearing.

Image courtesy of N. Maxwell Lander