September 29, 2011
Dinosaurs have been on-screen quite a bit lately. Dinosaur Revolution, Terra Nova and Planet Dinosaur have all brought a number of the prehistoric creatures—mostly carnivorous ones, of course—to television screens. We’re certainly not in want of scenes featuring sharp-toothed theropods chasing down hapless victims, human or otherwise, and Planet Dinosaur continued in the grand tradition of paleo-violence with the second and third installments of the documentary miniseries.
Episode two of Planet Dinosaur focuses on creatures vastly different from the stars of the first show. Instead of huge, carnivorous bruisers such as Spinosaurus and Carcharodontosaurus, we meet the small and feathered dinosaurs that once inhabited prehistoric China. Given the reluctance or inability of many dinosaur shows to depict fully feathered theropods, I was elated to see so many dinosaurs with plumage. And once again, the show did an admirable job of pausing the action now and again to inject some science.
Nevertheless, there were a few things about episode two that made me cringe. First was the flying Sinornithosaurus—as far as I am aware, there has not been a study suggesting this ability for the dinosaur. It appeared to be entirely a plot invention to put little Microraptor in peril (notice there was no “We know Sinornithosaurus was a glider because…” moment). What really made me facepalm, though, was the assertion that Sinornithosaurus was probably venomous. This idea was based on research that has been debunked—the structures thought to indicate a venomous bite were misinterpreted by the researchers who forwarded the hypothesis. I can understand why the show’s creators thought a venomous dinosaur would make an excellent clincher to episode two, but the science just isn’t there.
On to episode three. Whereas the first two episodes focus on a particular region, the third is wider-ranging and includes several different impressive theropods under the heading “Last Killers.” First up was Daspletosaurus, one of the lesser-known tyrannosaurs from North America. The predatory dinosaur is presented as part of a long-running evolutionary arms race with horned dinosaurs, but the only evidence is that both lineages became larger over time. The connection is tenuous. Furthermore, the frills and horns of the ceratopsian dinosaurs were so varied that their evolution was probably influenced by selective pressures such as the need to distinguish between species occupying the same landscape and, perhaps, competition between members of the same species for mates, rather than defense against tyrannosaurs or other predators. What we see as weapons that evolved for defense may actually be ornaments that primarily served in communication and competition among the horned dinosaurs themselves.
Planet Dinosaur also falls into the “dino gangs” trap. Just because multiple individuals of Daspletosaurus were found together does not necessarily mean that the dinosaurs lived in groups or hunted together. There are many ways to make a bonebed, and detailed study is required to figure out how all those bones came to rest in the same place. The idea of pack-hunting theropods is so strong, though, that it’s apparently difficult to dissuade documentary makers from going that route. In the show’s second vignette, a pack of the small, sickle-clawed predator Troodon was shown working together to take down a much larger hadrosaur, despite there being no evidence that these dinosaurs acted this way. (And, as pointed out in the recent description of the dinosaur Talos, many of the so-called “Troodon” fossils found across North America may truly belong to yet-undescribed genera and species, including those found in the Arctic.)
The show fares better with its Majungasaurus storyline. This was a different sort of predatory dinosaur—one of the stubby-armed abelisaurids—and Planet Dinosaur did a fair job fleshing out the fossil evidence suggesting that these dinosaurs sometimes cannibalized each other. (Paleontologists also proposed that Tyrannosaurus was an opportunistic cannibal on the basis of bite-damaged bones.) Our time with Majungasaurus is short, though. Planet Dinosaur quickly races back to meet Daspletosaurus during a migration of Centrosaurus at the finale.
Sadly, the second and third episodes of Planet Dinosaur sometimes fall prey to sensationalism rather than science. The show is at its weakest when science is either glossed over or ignored. While still better than many other recent documentaries, I still found myself being disappointed by these two installments in the series. And, on that note, we could use a documentary that doesn’t simply treat sauropods, hadrosaurs and horned dinosaurs as prey. Since the 19th century, restorations of dinosaurs have been so focused on prehistoric predators that it’s easy to believe that herbivores never did anything interesting outside of becoming a meal. There is far more to dinosaur science than figuring out just how vicious the tyrannosaurs were. Perhaps the next three installments of Planet Dinosaur will fare better than these two. At least, I hope so.
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