A new Living Planet Index report from the London Zoological Society and the World Wildlife Foundation says the world’s populations of wild animals are an average of half the size they were in 1970. The index tracked the populations of more than 10,000 representative populations of species from 1970 to 2010 and showed a bigger decline than previously thought (prior studies estimated that populations had declined by 30 percent). The report sites human consumption—and the resulting habitat loss—as the main reason for the decline. According to the report, there are only 3,000 tigers left in the wild today, as opposed to 100,000 a century ago. And Elephant populations in West Africa are living on about 7 percent of their historic land due to deforestation. You can check out the full report here for more information and ways to get involved to slow the decline …