Acid groundwater might percolate through the sand, dissolve the bone mineral, and leave nothing behind but a gross, misshapen carbon stain where a duckbill’s skull once lay. (Lifelike dinosaur costume)Or a sudden shift in a river’s course could erode part of the sedimentary layer it had deposited years before, and all the entombed bones would go tumbling down the new channel, breaking into irretrievable fragments. Paleontologists are grateful to streams for their blanketing of bones, but most streams also cannibalize. (Animatronic dinosaur costume)In one century they lay down deposits over the valley floor, in the next they might chew through their own sedimentary handiwork, churning and cracking buried bones and erasing the very fossil record they have previously preserved. The movie-film analogy allows us to visualize the frustrating process of investigating the Cretaceous. Instead of a continuous film, one frame a year for each of the last million years of the Mesozoic, only short bursts of film remain intact, each a few dozen frames together, separated by hundreds of feet of totally missing footage. (realistic dinosaur suit)If something important, like the final extinction of dinosaurs, happened suddenly, within a few years, we wouldn’t have a prayer of catching the deed in the film clips of sediment.
The best detective stories are those that command our rapt attention to every scrap of clue, so that we can solve the crime in the final chapter, just before the sleuth announces the identity of the murderer. Dinosaur extinction attracts the best of paleontological detectives. Up to Bug Creek and Hell Creek they go, digging quarries, running sediment through fine sieves to sift for the tiniest of bones and teeth. But much of the mystery remains. (animatronic dinosaur)Only a few facts are clear. The final dying was sudden, compared to the immense length of the history of the dinosaurs: It took no more than two million years—maybe much less—to exterminate all the Cretaceous dynasties. And there were opportunists waiting around for the dinosaurs to die: small, furry, insect-eating, berry-chewing mammals scurrying around the underbrush, fidgeting about, grooming their whiskers.
As the dinosaurian clans were thinned out, with the extinction rate exceeding the production rate of new species, these Late Cretaceous furballs expanded their ecological sphere of influence. (animatronic dinosaur for sale)The fossils show new types of small, mammalian plant-eaters and insectivores blossoming in Montana at the very time the evolutionary fortune of the dinosaurs was sinking into its final, irrevocable decline. Passing upward through the sedimentary pile in Montana, exposed now in dry gulches, we can see the shifting census of evolutionary success. The mammals were diversifying rapidly near the very end of the Cretaceous, and dinosaurs dwindled until a level is reached in the layer of mud and sand through which no species of dinosaur passed. This layer marks the end of the Lancian Epoch, the end of the Cretaceous, the end of the Mesozoic. This time the dinosaurs would not recover.