Dinosaurs and Modern Mammals Developed Comparable Traits by Ted Bailey
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Refuge Notebook • Vol. 5, No. 4 • January 24, 2003 Dinosaurs and modern mammals developed comparable traits by Ted Bailey Although the dinosaurs and today’s mammals are cause they lacked plant-grinding teeth, just as modern separated by more than 65 million years—an immense spruce grouse pick up gravel for grinding food in their gap of time too great for our minds to comprehend— gizzards. many of the dinosaurs developed traits comparable to The next generation of plant-eating dinosaurs gave those of today’s modern mammals. These similarities up the rock-and-gizzard approach, and developed became evident to me during the past several months complex plant snippers and plant-grinding teeth. Fast- while I was teaching a class entitled “The Dinosaur Re- forward roughly 70 million years to the present day naissance” at the Kenai Peninsula College. Although and we see similar mechanisms for plant snipping and some may still believe dinosaurs were obsolete, dumb, plant grinding in today’s moose, caribou and many giant “lizards” that were driven to extinction by the other hoofed mammals. These mammals snip off plant efforts of “advanced” mammals, this is untrue. Most parts in the front of an elongated mouth with spe- scientists now believe the demise of the dinosaurs was cial teeth or bones, and then pass snipped-off parts caused by a catastrophic event, probably an asteroid through a toothless gap in the jaw to the back of the impacting the earth with devastating worldwide en- mouth where highly specialized teeth are used to grind vironmental destruction, rather than by any lack of up the plant tissue into small pieces for efficient nu- adaptability on the part of the dinosaurs. An assess- trient extraction. Thus, many of today’s “advanced” ment of the various adaptations of dinosaurs reveals mammalian herbivores are using some of the same ba- that many dinosaurs were superbly adapted to their sic feeding mechanisms that the dinosaurs developed environment, not unlike today’s mammals. millions of years ago. Unlike many people who became fascinated with One of the most agile and intelligent predatory dinosaurs as a child, I became interested in them in dinosaurs was a species paleontologists have named middle age, specifically in 1975, the year my family Troodon. It had one of the largest brains relative to and I returned to the United States after living for two its body size of any dinosaur. Its method of locomo- years in Africa. That was the same year that a maver- tion was bipedal, similar to the method used by to- ick paleontologist named Bob Bakker published an ar- day’s famous bird of the southwest—the roadrunner. ticle entitled “The Dinosaur Renaissance” in the mag- Troodon’s rear leg bones and other features indicate azine Scientific American. In that article he proposed it was also swift running; its large eyes set partially that unlike previous views of dinosaurs as lethargic forward in its head indicated it probably had binoc- cold-blood reptiles, new evidence suggested that di- ular vision for depth perception. Its arsenal also in- nosaurs were warm-blooded animals—like mammals cluded flexible, grasping front hands with sharp re- and birds—and that some were very active, agile and curved claws. It may have been a stalker or a fast pur- intelligent. That article and later his book Dinosaur suer or perhaps both but regardless, it was an efficient Heresies initiated a revolution in the study of dinosaurs two-legged predator well adapted to capturing elusive that continues unabated today. And since then, I have prey. attempted to keep informed of the latest findings. A close relative of Troodon was Velociraptor. It had Here are a few examples of dinosaur adaptations the same features but was smaller and weighed only compared to mammal adaptations with which we are about 33 pounds. I find several similarities between familiar, including mammal adaptations on the Kenai Velociraptor and the modern lynx. The lynx, like many Peninsula. The earlier, more primitive and famil- wild cats, has a relatively large brain; it is intelligent iar plant-eating dinosaurs—the giant sauropods like and has large forward-looking eyes with binocular vi- Brontosaurus and Brachiosaurus—swallowed stones sion for depth perception. A lynx can either secre- (gastroliths) to help grind up the plants they ate be- tively stalk or swiftly pursue its prey, usually a snow- USFWS Kenai National Wildlife Refuge 7 Refuge Notebook • Vol. 5, No. 4 • January 24, 2003 shoe hare, then grasp it in its claws while delivering a breasted nuthatches and others—are actually nothing lethal bite. By the way, Velociraptor was the intelligent less than small, feathered dinosaurs whose ancestors and cunning dinosaur portrayed stalking humans in somehow survived the great extinction event 65 mil- the movie Jurassic Park. Those swift, agile, intelligent lion years ago. I find it even more remarkable that and misnamed “Jurassic” Park dinosaurs were actually some of these flying “dinosaurs” have adapted so well modeled on yet another larger but related predatory to exceptionally harsh environments including our dinosaur Deinonychus, a species that also had many of cold, dark and snowy Alaskan winters. the same features as Velociraptor and Troodon, includ- Ted Bailey is a retired refuge wildlife biologist who ing a large sharp claw on each hind foot. Deinonychus has worked on the Kenai Peninsula for over 25 years. He are thought to have hunted in packs—like wolves—to is an adjunct instructor at the Kenai Peninsula College bring down prey much larger then themselves. and maintains a keen interest in the Kenai Peninsula’s I find these similarities between dinosaurs and to- wildlife and natural history—and in dinosaurs. For more day’s mammals fascinating. And I get great satisfac- information about the Refuge, visit the headquarters in tion watching the living descendents of the dinosaurs Soldotna, call (907) 262-7021. Previous Refuge Notebook in my backyard and on winter walks. Yes, most biol- columns can be viewed on the Web at http://kenai.fws. ogists and paleontologists believe that today’s birds— gov. our familiar black-capped and boreal chickadees, red- 8 USFWS Kenai National Wildlife Refuge.