Related by context. Frequent words. (Click for all words.) 57 overcrowding 52 environmental degradation 51 urban sprawl 48 social ills 48 global warming 48 feral cats 46 suburban sprawl 45 urbanization 45 Global warming 43 crowding 43 homelessness 43 ecological 43 predation 43 climate change 43 scarcity 43 inequality 42 deforestation 42 illegal immigration 42 starvation 42 unwanted pregnancies 42 euthanasia 42 extinctions 42 desertification 42 underdevelopment 41 soil erosion 41 birthrate 41 teen pregnancy 41 stray cats 41 overfishing 41 sprawl 41 spaying 41 euthanize 41 overabundance 40 traffic congestion 40 deer herd 40 Global Warming 40 carnivores 40 extinction 40 obesity epidemic 40 infant mortality 39 inequity 39 eugenics 39 malnutrition 39 environmentalism 39 epidemic 38 animal shelter 38 inhumane 38 neutering 38 puppy mills 38 extermination 38 humane 38 militarization 38 habitat 38 stray animals 38 pollution 38 invasive species 38 greenhouse gasses 37 euthanized 37 animal cruelty 37 spay 37 spay neuter 37 epidemics 37 Population 37 depletion 37 ills 37 overcrowded 37 wildlife 36 biodiversity 36 hunger 36 inequalities 36 stray dogs 36 conservation 36 cruelty 36 poverty 36 degradation 36 antibiotic resistance 36 algae blooms 36 animals 36 childhood obesity 36 teenage pregnancy 36 habitats 36 gentrification 36 mountain lions 36 imbalances 36 illiteracy 36 plaguing 35 proliferation 35 religious extremism 35 humane society 35 population 35 populations 35 societal 35 coyotes 35 vegetarianism 35 raccoons 35 root causes 35 problem 35 poaching 35 evils 35 wildlife conservation 35 infertility