No, they’re not dinosaurs. These critters are much more recent than the 60 million years since dinosaurs walked the Earth. In fact, our own species may be in part responsible for their demise. They were the top predators of Ice Age North America, and while the cause of their extinction is still subject to debate, they died out, along with their prey, shortly after humans first migrated into the Americas.
The DVD has National Geographic programs on three animals: the saber-toothed cat, the dire wolf, and the short-faced bear. Fossils of all three are found in the La Brea tar pits, and the excavations at La Brea are repeatedly discussed on the DVD. It is subject to the usual bias of this series: good interviews with scientists; poor quality animation clips which are repeated over and over. Another problem is that the science is posed on a “proof” basis when in fact science works by disproof. In general the narrator speaks of “proof” when the scientist involved has shown that his or her hypothesis as not been disproved. This is a very common problem with National Geographic science DVDs.
All three animals hunted the same mega-herbivores: bison, horse, and mammoth. In the same habitat they selected somewhat different prey. Camel and (for the short-faced bear) ground sloth may also have been on the menu, but all three predators were specialized to go after very large prey.
The saber-toothed cat was no more a tiger than it was a house cat. Its weight was in the same range as the modern lion, but it was far stockier and more muscular, with a short tail which reduced its agility at a run. It probably was much more of a wrestler than the modern large cats, and a fair part of the program is devoted to the question of how it used its saber-like but brittle canines for killing. It’s not as obvious as it seems; those oversized canines would have slid off the rounded belly of a prey animal. Nor was its skull constructed for a hard bite. But I have a feeling that it may have used its momentum more than the video clips suggest in pulling down a large animal. (I suspect also that any mammoths it killed were young, very old, or injured. I have a highly unsuccessful saber-tooth attack on a mammoth calf with its mother close by in Tourist Trap.)
The dire wolf closely resembled the modern gray wolf, but was considerably larger and sturdier, with greater bite strength. It probably ran in larger packs than modern wolves, but is thought to have had a very similar hunting style. I suspect the video clips show a far more immediate pulldown of prey than actually occurred. With very large herbivores thick on the ground, the dire wolf would have been an advantage over the gray wolf. When only smaller game became available, the faster, lighter, more behaviorally flexible gray wolf survived and the dire wolf did not.
The third of the predators, the short-faced bear, may not have been a predator so much as a scavenger, stealing kills from the other large predators. It was a very large bear, larger than the largest of the modern grizzlies, such as Kodiak bears. Its legs, however, were relatively long and slender, and it seems to have built for efficiency of gait rather than speed. It probably had an exceptional sense of smell (modern grizzlies have a better sense of smell than bloodhounds) so it was actually well adapted for stealing the kills of other predators. Certainly grizzlies today steal wolf kills if an opportunity occurs. But as I said, possibility or even probability is not scientific proof.
As an introduction to these three Pleistocene predators, this DVD is definitely worth watching. But don’t take everything it says too literally.