Taphonomy Before burial

Consider what happens to a dinosaur - or any land-dwelling vertebrate -when it dies. If it is killed, it can be disarticulated (dismembered), first by the animal that lolled it, and then by scavengers. In modern environments, the best known of these scavengers are vultures or hyenas, but there are smaller animals of far greater significance, such as scarily efficient carrion-eating dermestid beetles. Of course most of the heavy lifting in the world of decomposition is done by bacteria that feast on rotting flesh (leaving no doubt that something died). The bones are commonly stripped clean of meat and occasionally left to bleach in the sun. Some bones might get carried off and gnawed somewhere else. Sometimes the disarticulated remains are trampled by herds of animals, breaking and separating them further. The more delicate the bones, the more likely they are to be destroyed. So there sit the sum of all the earthly remains of the animal: a few disarticulated bleached bones lying in the grass.

If the animal isn't killed by some predator but just dies (old age, drowning, and disease all qualify) it may or may not be disarticulated immediately, depending upon which scavengers get to it and when (Figure 1.1). Left intact, it is not uncommon for a carcass to swell up (bacterial decomposition produces gasses that inflate it), eventually deflate (sometimes catastrophically: this can be just a tad grotesque), and then dry out (if not in water), leaving bones, tissues, ligaments, tendons, and skin hard and inflexible. The tissues shrink as they dry, bending the limbs and pulling back the head and lips into a hideous rictus (producing the illusion that the animal died in agony). Under such conditions, the creature is essentially mummified, and the carcass can be exposed for a very long time without further decomposition. Then we get "jerky": dried meat that resists decomposition. Later in this book, we will encounter genuine dino jerky.

Occasionally catastrophic things happen to herding animals. Floods catch herds as they cross swollen rivers and there are mass drownings. The carcasses may bloat and float, eventually to pile up along the edge of a channel, wash up onto a floodplain, or accumulate on the surface of a point bar at bends in the waterway. Left alone, the bones may be stripped, partially disarticulated, and bleach in piles of semi-articulated skeletons of one type of animal.

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