africa animals bears behavior climaticchanges ecology effectofhumanbeingson endangeredspecies environmentalaspects environmentalconditions environmentaldegradation grasslandecology greatplains herbivores history human-animalrelationships juvenileliterature lift-the-flapbooks nat046000nat044000nat003000 naturalhistory nature predatoryanimals specimens toyandmovablebooks wildlifeconservation wolves zoology