Related by context. Frequent words. (Click for all words.) 54 vocalisations 51 Sinervo 49 zoologists 49 Frans de Waal 49 Willerslev 48 Deisseroth 48 mole rats 48 vocalizations 47 primatologist 47 echolocation 47 palaeontology 46 howler monkeys 46 termite mounds 46 olfaction 46 Poinar 46 hornbills 45 Evolutionary biologists 45 African savannah 45 zebra finch 45 birdcalls 45 neurobiologists 45 soundwaves 45 Indohyus 45 vocalization 44 Ngorongoro Crater 44 Paabo 44 zoologist 44 infrasound 44 mating habits 44 primatologists 44 okapi 43 termite mound 43 mammal 43 Lake Natron 43 Namib Desert 43 echidnas 42 Louis Leakey 42 Kiecolt Glaser 42 mating rituals 42 Dian Fossey 42 undersea volcanoes 42 zebra finches 42 Svante Paabo 42 behavioral ecologist 42 bonobo 42 paleoclimate 41 bird migrations 41 mammals 41 bonobos 41 neurophysiology 41 paleoanthropology 41 Chiappe 41 Marzluff 41 habituation 41 chimpanzees 41 ichthyosaur 41 Kalahari Desert 41 toadfish 41 screeching noise 41 paleontologists 41 predator prey 41 hippos 41 paleontology 40 substorm 40 Biology Letters 40 African savanna 40 Nile crocodile 40 Jane Goodall 40 baboons 40 mooing 40 Zoologists 40 elephants 40 microfossils 40 Ornithologists 40 ungulate 40 zebras 40 avians 40 spoor 40 biogeochemical 40 nocturnal creatures 40 hominid species 39 Changizi 39 Snowball Earth 39 researchers 39 tapirs 39 scientists 39 antelopes 39 Beluga whales 39 alien civilizations 39 Seracini 39 Changnon 39 Cambrian explosion 39 rustling leaves 39 Palumbi 39 Poldrack 39 chimps 39 palaeontologist 39 wood thrush 39 biologists 39 Keck Observatory 39 meerkats