Related by context. Frequent words. (Click for all words.) 68 mammoths 65 Pleistocene 64 dinosaurs 64 woolly mammoths 61 mammals 61 Homo sapiens 60 mass extinction 60 Neanderthals 59 species 59 glaciation 59 hominids 58 extinctions 58 mass extinctions 58 herbivores 58 woolly mammoth 57 marsupials 57 hunter gatherers 56 fossils 56 mastodons 56 mammal species 56 prehistoric 56 sauropods 55 volcanism 55 mammal 55 hominid 54 Ice Age 54 frog species 54 carnivores 54 extinct species 53 Homo erectus 53 vertebrate 53 glaciers 53 fossil 53 Cretaceous 53 amphibian species 53 prehistory 53 Little Ice Age 52 amphibians 52 dinos 52 palaeontologists 52 taxa 52 plate tectonics 52 herbivore 52 T. rex 52 sauropod 52 diatoms 51 vertebrates 51 paleontological 50 dinosaur 50 speciation 50 radiocarbon dating 50 dinosaur fossils 50 marine ecosystems 50 atmospheric carbon dioxide 50 mountain glaciers 50 primate species 50 lineages 50 Extinct 49 genetic diversity 49 biosphere 49 extinct 49 flowering plants 49 hunter gatherer 49 apes 49 ecosystems 48 koalas 48 Komodo dragons 48 toads 48 tropical forests 48 humans 48 interbreeding 48 paleontologists 48 bird species 48 corals 48 marmots 48 Triassic 48 elephant seals 48 eukaryotes 47 evolutionary biologists 47 grasslands 47 atmospheric circulation 47 fur seals 47 Prehistoric 47 Neanderthal 47 atmospheric CO2 47 grizzlies 47 fossilized remains 47 coral species 47 paleo 47 permafrost 47 dingoes 47 organisms 47 leatherbacks 47 carbon sinks 46 arthropods 46 habitats 46 grizzly bears 46 wolverines 46 sediments 46 primates 46 homo sapiens