Related by context. Frequent words. (Click for all words.) 51 Pleistocene era 49 mammoths 43 Arctic permafrost 42 Cretaceous Period 42 brontosaurus 41 H. erectus 41 dinosaurs 40 interglacial 40 dinosaurs roamed 40 permafrost 39 wooly mammoth 39 interglacial period 39 Pleistocene 39 Mummified 39 Arctic tundra 39 temperate forests 39 fossilized 39 Mesozoic 39 Homo Sapiens 39 Ice Age 39 Otzi 38 dinosaur 38 Late Cretaceous 38 woolly mammoths 38 homo sapiens 38 radiocarbon 37 mummified 37 Carboniferous 37 mass extinction 37 Microorganisms 37 tar pits 37 fossilized remains 37 African savanna 37 Neanderthal 37 prehistoric 37 oxygen isotopes 37 tyrannosaurus rex 37 Giant pandas 37 Cretaceous 37 Tyrannosaurus rex 37 hominid 37 cave dwelling 37 Pliocene 37 genus Homo 36 gigatonnes 36 Precambrian 36 Poinar 36 carbonite 36 woolly mammoth 36 Paleontologists 36 locked 36 megafauna 36 Industrialized nations 36 supercontinent 36 trilobites 36 Zimov 36 eons 36 Eocene 36 hominins 36 Homo sapiens 36 single celled organisms 36 Tyrannosaurus Rex 35 glaciation 35 Ellesmere Island 35 T rex 35 Niels Bohr Institute 35 triceratops 35 coprolites 35 kelvin 35 icecaps 35 fossil 35 planet Krypton 35 cave 35 marine reptiles 35 gigatons 35 atmospheric methane 35 Younger Dryas 35 subarctic 35 dinos 34 age 34 Neandertals 34 fossils 34 hominids 34 giant tortoise 34 Oetzi 34 solar nebula 34 African savannah 34 Australopithecus 34 extinctions 34 domesticated 34 co2 34 T. rex 34 musk oxen 34 radioactive decay 33 preindustrial 33 Homo floresiensis 33 Homo erectus 33 prehistoric creatures 33 Antarctic ice 33 mastodons 33 polar ice