The sophistication of your knowledge about dinosaurs is generally restricted by how long ago your children went through their dinosaur period.
Even the simplest of kids' picture books shoots down the image of lumbering bloodthirsty beasts that was fodder for the fascinated baby boomer 35 years ago. Hey, silly, they didn't drag their tails, otherwise we'd have found tail tracks with their footprints. Don't you know that, Dad?
Even now, if it's been a few years since your child was finding out that the apatosaurus and the brontosaurus were one and the same, you might think that the brachiosaurus was the biggest dinosaur of all, not knowing about the few bones found of the ultrasaurus or seismosaurus.
Or maybe you, raised on the mammals-ate-their-eggs theory of extinction, think that the meteorite-caused mass death is still avant garde, not knowing that revisionists are already knocking it down.
Or how about the latest views of dinosaurs as caring parents, carnivores traveling in herds and protecting their young as a group of herbivores such as triceratops graze peacefully like a wildebeest on the veldt. Such images are even now being worked up for the rising generation of 4-year-olds.
And that's because, though dinosaurs are a phase for most, for a few they become an obsession that plods -- tail held high -- right into adulthood. You can learn about such folks starting tonight as PBS' "Nova" begins its own bit of sweep-month stunting, three weeks of programs about dinosaurs.
The opener, which will be on Maryland Public Television, channels 22 and 67, at 8 o'clock, is "The Hunt for China's Dinosaurs." It goes along with two expeditions to China's Gobi Desert, considered one of the world's hottest dinosaur fossil spots but closed to western scientists for 60 years.
This crew from Canada was following in the footsteps of Roy Chapman Andrews, described in the narrative as a real-life Indiana Jones, who pulled and tugged bones and skeletons and eggs from the Gobi's rocks back in the 1920s.
Andrews had a Hollywood cinematographer along. This group has some cameras from "Nova." The results this time might not be quite as romanticized but are still fascinating as these Canadians and Chinese examine this bleak landscape looking for evidence of the thunder lizards.
The first expedition to the western Gobi in 1987 almost struck out until it found a protruding bone. Using everything from
dynamite to toothbrushes, it uncovered as much of the skeleton of a huge 100-foot-long sauropod as time allowed.
This same group returned to the even more remonte eastern Gobi three years later to find a treasure trove of fossilized remains and, even more heartwarming, evidence that they were literally following in Andrews' footsteps.
Next week's second hour, "The Case of the Flying Dinosaur," is an interesting, if a bit arcane, examination of a tempest in the evolutionary teapot, the controversy about whether or not birds are the descendants of dinosaurs. It's a rather captivating thought, actually, that the genetic survivors of those huge beasts are the most delicate and graceful creatures on Earth, defiers of the gravity that weighed so heavily on their supposed ancestors.
The final of the three shows, airing Tuesday, Feb. 19, is actually the most accessible and should have led off the trio. "T. Rex Exposed" chronicles the summer-long excavation of a Tyrannosaurus Rex skeleton from a rock outcropping in Montana as it examines competing theories about the nature of this most legendary of dinosaurs.
Some scientists now think that tyrannosaurus, historically depicted as a fearsome predator, would have had a tough time in a battle with no weapon but its teeth. They believe instead that its huge jaw was equipped for the elaborate butchering needs of a scavenger.
Others, however, argue that tyrannosaurus' huge muscles and relative agility are proof that this was one mean fighting machine. Along the way, "T. Rex Exposed" exposes much of the methodology of those who study dinosaurs, something that can be as sophisticated as subjecting a tyrannosaurus skull to a CAT scan, and as basic as just sitting around thinking about what some animal could have done with those long teeth and short arms.
In the end, though, it is a human arm's-length illustration of dinosaurs' span of time on Earth that is most memorable. If the arm represents the length of time life has been present on land, dinosaurs go from mid-bicep almost to the wrist. Human beings are in the very tip of the finger. These aren't the plodding beasts bested by the smart, quick mammals of long-ago, they were magnificent machines that can teach us bumbling Homo sapiens something about survival.