Yaël: Don, when I say "dinosaur" what do you picture?

 

Don: Huge reptile-like creatures like Tyrannosaurus rex or the long-necked brachiosaurus?

 

Y: Me too, but do you know there were also tiny dinosaurs? In recent years, palaeontologists have unearthed some of the smallest dinosaurs known. In the late  1990s two tiny species of Theropods were discovered in China and Mongolia. The  Theropod group contains carnivorous dinosaurs that walked on two legs, like T. rex and velociraptors. The newly discovered "tiny-osaurs" were both under two feet long  and probably weighed less than your Thanksgiving turkey.

 

     In 2002, the smallest North American dinosaur was uncovered in Alberta, Canada. This puny Theropod is also unique because it probably dined on insects. Most other Theropods were meat-eaters.

 

D: How do we know these aren't just fossils of baby dinosaurs?

 

Y: One way to tell is by examining the growth rings in bones. In some bone tissue, layers  are created as the bone grows, sort of like the rings of a tree. The bones of older animals grow more slowly, so the rings get closer together. This allows scientists to identify if the bones are from adults or juveniles.

 

     Another way to tell is when several fossils are found together that include adults and   juveniles---like the discovery of the smallest Sauropod species in Germany in 2006.

 

     The Sauropod group contains the giant, long-necked, plant-eating dinosaurs that   walked on four legs---like the eighty-foot long brachiosaurus. But the new species    from Germany are much smaller---about twenty feet long as adults, and some   juveniles are only four feet long.

 

D: Well, now when I think "dinosaurs" I'll think "teenie-weenie."