Romancing the Raptor : The Dino Finally gets Heroine Status : THE LOST WORLD, <i> By Michael Crichton (Alfred A. Knopf: $25.95; 393 pp.)</i> : RAPTOR RED, <i> By Robert T. Bakker (Bantam: $21.95; 246 pp.)</i>

Michael Crichton, long condemned for his cardboard fictional characters, is in fact often quite good at fleshing out fiendish villains. Consider the raptor, the bantamweight dinosaur of “Jurassic Park,” Crichton’s 1990 blockbuster that sold 10 million copies and inspired the most popular movie of all time.

There, he took a relatively pint-sized and popularly unknown predator out of the chorus line of dinosaurs, and convincingly placed the species up with the tyrannosaur in the pantheon of the all-time most feared and respected lizards. While Crichton’s mountainous T-Rex bellowed unknowingly and numbly munched heads like gum balls, his raptors were snarling, cruelly intelligent beings who hunted in packs and strategically butchered with their feet. Thanks to Crichton, a villainous star was born.

Now, with “The Lost World,” the sequel to “Jurassic Park,” the raptor is back, seemingly meaner, more loathsome, and once again better developed than almost all of the book’s human characters. This isn’t a slam on the author whose latest book comes accompanied by a “Time” magazine cover story and a 2-million-copy first printing: One doesn’t read Crichton’s books for intimate peeks at inner worlds, but for heaping helpings of plot, suspense and cosmological maunderings from popular literature’s most noted polymath.

One of the book’s dominant discourses is on extinction theory. In “The Lost World,” scientist Iam Malcolm, a returnee from “Jurassic Park,” announces that “extinction is the inevitable result of one or the other strategy--too much change, or too little. “ Likewise with sequels. But in “The Lost World,” Crichton’s first encore, the author has done the sequel step just right, keeping the tropes of the earlier novel familiar for the fans while changing the ideas and story line enough to keep even his severest and most envious critics turning the pages to find out what happens next.

As things turned out, all the scientifically engineered dinosaurs were not killed when the amusement park surrounding them in the Costa Rican jungle was destroyed at the end of “Jurassic Park.” Now, six years later, another expedition of scientists and cuddly kids is off to explore the phenomenon, followed by a group of bad guys who, among other things, would like to clone dinosaurs for use as fodder for big-game hunters. “How many,” asks the evil Dodgson, “can claim to have a snarling tyrannosaurus head, hanging above the wet bar?”

Also included is a smorgasbord of ideas about everything from the nature of chaos, evolution and numbers theory to references to Avogadro’s number, Planck’s constant, and Heisenberg’s sense of uncertainty. Humans, meantime, are introduced as if in shorthand screenplay form: “Sara Harding had been a poor scholarship student at the University of Chicago but now, at 33, she was an assistant professor at Princeton. She was beautiful and independent, a rebel who went her own way.”

Once again, the dinosaurs seem the real stars. T-Rex, this time, seems strangely mellowed as Crichton shows the mother and father tyrannosaurs gently caring for their brood, relying on each other like Ma and Pa Kettle, and even seeming to pause to consider before stomping the humans who desecrated their family nest.

But it is the raptors who once again get the nastiest scenes and most malevolent descriptions. Not even their housekeeping gets good marks; upon coming upon anunmistakable sense of order. “ Like the newly minted rock stars Crichton has turned them into, raptors have raptor home, the scientist Levine thought the “nest appeared slovenly, uncared for, ill-made.” He was surprised because dinosaur nests usually conveyed an learned the first rule of show biz: Trash your suite.

A raptor of an entirely different sort is the heroine of Robert T. Bakker’s charming “Raptor Red,” a novel written from the perspective of a widowed predator trying to make her way in the plains of Utah 120 million years ago. Bakker, dinosaur curator of the Tate Museum in Wyoming, wears his bias on his sleeve, announcing in his author’s note that he “is most famous for proposing the stunning theory that dinosaurs weren’t the cold-blooded, sluggish, solitary creatures we once imagined them to be, but were instead warm-blooded, active and social animals.”

Perhaps none were so warm as Raptor Red, the struggling heroine, who we meet as she and her beloved mate stalk a hulking “Astrodon” with the comradely efficiency of a functional couple running a family business. Tragedy strikes when the male raptor gets trapped in a mud flat and drowns in front of her eyes; “now as she sits in the mud next to her dead mate,” the book reports, “she experiences feelings that are new: despair and loneliness.”

Now that is a character. With her loss, Raptor Red emerges as a kind of prehistoric version of Mary Richards from “The Mary Tyler Moore Show.” Red, a proud, attractive, childless single woman determined to make her way in the world alone until she can find the perfect mate, will certainly be granted the affections of the “yellow snouts,” those inappropriate suitors from other raptor clans who she knows are bad for her. But she wants more.

The book paints an illuminative tapestry of the age with little of the pedantry that sometimes invades Crichton’s lectures. Setting off on her own, Red finally joins up with her sister’s family and trots on to the ocean in search of both that mate and safe haven from the predators who want her. Equal parts science tale and love story, the novel succeeds as sharing and caring alternative--albeit one sprinkled with interludes of gore and mayhem--to Crichton’s picture of the raptor as a reptile fascist.

“My mate is the most beautiful raptor in the world,” thinks Red’s eventual pick, a year after her loss. And though the words come out a little more leaden than in Crichton’s page-turner, the overall effect is more fetching. The dinosaurs didn’t last forever, but in Bakker’s book, they at least seem to breathe.

“The Lost World,” read by Anthony Heald, is available on four audiocassettes from Random House ($23.50; abridged). “Raptor Red,” read by Megan Gallagher, is available on two audiocassettes from Simon & Schuster ($17; abridged).