Related by context. Frequent words. (Click for all words.) 65 extinction 63 extinct species 61 Extinct 57 dodo 56 critically endangered 55 extirpated 55 subspecies 54 dodo bird 54 species 52 genetically distinct 52 endangered species 51 endangered 50 dinosaurs 50 Critically Endangered 50 domesticated 49 megafauna 49 vertebrate species 49 amphibian species 49 mammal species 49 dinosaur 48 exterminated 48 Endangered 48 fossilized 48 prehistoric 48 frog species 47 interbred 47 mastodons 47 homo sapiens 46 mammal 46 flightless 46 mammoths 46 extinctions 46 disappearing 46 overhunting 46 disappear 45 critically endangered species 44 Homo habilis 44 thylacine 44 breeding pairs 44 Extinction 44 obsolete 44 mammals 44 coelacanth 43 Homo sapiens 43 clouded leopard 43 keystone species 43 Mammoths 43 breeding colony 43 Endangered Species List 43 fossils 43 Species 43 theropods 43 baiji 42 penguin species 42 eradicated 42 Homo floresiensis 42 zoologists 42 lineages 42 Neanderthals 42 woolly mammoth 42 fossil 42 flightless birds 42 Archaeopteryx 42 carnivorous 42 woolly mammoths 41 hominid 41 sauropod 41 tyrannosaurs 41 sauropods 41 species extinctions 41 Homo erectus 41 mass extinction 41 hibernation 41 rhinoceroses 41 primate species 41 endemic 41 IUCN Red 41 herbivorous 41 genus 41 overexploited 41 bird species 41 Threatened Species 41 flightless bird 41 vertebrates 40 amphibians 40 interbreeding 40 dying breed 40 Orangutans 40 nesting pairs 40 rendered obsolete 40 hunter gatherer 40 colonized 40 Longrich 40 Fertile Crescent 40 palaeontologists 40 captive bred 40 genera 40 vanishing 40 Grizzly bears 40 hominids 40 common ancestor