Misconceptions about dinosaurs could fill several bad movies, and certainly have.

For decades, says Dr. Robert Bakker, we have assumed the worst about these hapless creatures: that they were plodding, stupid and bad mothers, too.But none of it's true, says Bakker. And they're not extinct, either, he adds.

Bakker, the author of "Dinosaur Heresies," will be in Salt Lake City on Wednesday to dispel these and other myths. His lecture, at 7:30 p.m. at Kingsbury Hall at the University of Utah, kicks off the Museum of Natural History's Dinosauria Lecture Series. Tickets for the series, the latest in a yearlong celebration of "Utah's oldest residents," are $1.

Bakker, a paleontologist at the University of Colorado Museum in Boulder, says he doesn't know where all the misconceptions about dinosaurs came from. Maybe all those dumb horror movies but "not from careful analysis of the facts."

The truth about dinosaurs, he says, is that:

- They weren't slow. Their legs were incredibly strong, says Bakker. "They were much stronger than two-ton rhinos. And I know how fast two-ton rhinos are, because I was chased by one in Africa. They do at least 30 miles per hour."

Dinosaurs had a cruising speed that was "way up there." The tyrannosaurus rex was faster than a wolf, he says.

- They weren't all stupid. Some had tiny brains, to be sure. But the smarter ones were definitely as smart as the modern road runner. Or a dog.

- They weren't bad mothers. People have assumed that, but a study of dinosaur tracks turns up no baby tracks without adult tracks nearby. "They were surrounded by adults," says Bakker.

- They weren't cold-blooded. Bakker arrives at this conclusion based on some of the other conclusions. "Only warm-blooded animals cruise fast and grow fast," he explains. "Some dinosaurs grew to be 30 tons by the time they were 10 years old."

- They aren't extinct. They just evolved. Birds, he says, "are living dinosaurs."

As you can probably guess, such notions were not well-received when Bakker started espousing them 20 years ago. "The reaction from the orthodoxy was `string him up!' " says Bakker.

Now, however, paleontologists are going back to beliefs held a century ago. "More and more the common perception is that dinosaurs were big birds, not big lizards," he says.

Bakker has been hooked on dinosaurs since he saw a "Life" magazine article about them in 1954, when he was in the fourth grade.

"They're nature's special effects," he says, still in awe.

The museum's Dinosauria Series will continue for three more Wednesdays. On Oct. 26, paleontologist John R. Horner from the Museum of the Rockies in Bozeman, Mont., will speak on "Family Life of Dinosaurs," at 7:30 p.m. at the U. of U.'s Fine Arts Auditorium.

On Nov. 2, paleontologist Daniel J. Chure of Utah's Dinosaur National Monument will speak at 7:30 p.m. at the Fine Arts Auditorium. Focusing on the Dinosaur National Monument, he will explore landscape and animals that co-existed with dinosaurs of the late Jurassic period.

On Nov. 9, author Donald F. Glut will speak at 7:30 p.m. at the Fine Arts Auditorium on "Fantasy Dinosaurs of the Movies." Glut, the author of several dinosaur books and of the novelization of "The Empire Strikes Back," will show clips from old dinosaur movies, including early silent classics such as "Gertie the Dinosaur."