TV REVIEWS : ‘Dinosaurs’: Alive and Kicking on PBS

“Are dinosaurs kosher?”

Paleontologist Robert Bakker casually drops the seemingly ludicrous question into a conversation to reflect rapidly changing ideas about the nature of dinosaurs. Jewish dietary law forbids the consumption of creatures that crawl on their bellies, and 25 years ago, the prevailing view of many dinosaurs as reptilians fit that image.

Today, however, it has become clear that some dinosaurs were agile, hot-blooded ancestors of birds. Some, like the maiasaur, raised their young in closely packed nests like birds along the seashore. Like birds, they had color vision and females were larger than males.

“If birds are kosher,” Bakker concludes, “then dinosaurs are too.”

The rapid change in knowledge about dinosaurs is the focus of a new four-part series, “The Dinosaurs,” beginning Sunday evening and continuing through Wednesday (at 8 p.m. on KCET-TV Channel 28 and KPBS-TV Channel 15, at 10 p.m. on KOCE-TV Channel 50 and at 7 p.m. on KVCR-TV Channel 24).

Dinosaur series have been a staple of educational television. Every year, it seems, another expensively produced series has come along to extol the wonder and explore the mysterious demise of these fascinating behemoths 65 million years ago.

So why do we need another series? Because ideas about dinosaurs have changed so fast that previous programs have become dated almost as soon as they have aired. That fate may also befall “The Dinosaurs,” but it provides a compelling picture of what is known right now, amply illustrated with scenes shot at 50 locations around the world and with animation that may provide the first correct picture of how dinosaurs really behaved.

So what is new?

* Many dinosaurs were warmblooded, more like ferocious lions and tigers than like crocodiles and lizards.

* They migrated in massive herds that may have summered in the Arctic and wintered in more comfortable climes.

* Some were very familial, succoring their nestlings until they were old enough to fend for themselves.

* Because they had color vision, like modern birds, dinosaurs undoubtedly existed in a broad ranges of hues, blending into their surroundings for protection from their more voracious brethren.

* Although disease may have had much to do with the dinosaurs’ extinction, a major role was almost certainly played by a 6-mile-wide comet that struck the Yucatan Peninsula at the end of Cretaceous period.

That comet, which subjected the world to a “nuclear winter” that may have persisted for years, was a catastrophe for dinosaurs, but was a blessing for humankind. If the intensely predatory dinosaurs had not been eradicated, paleontologists now conclude, humans could never have evolved.