Peter Shawl discusses the main threats to wildlife. He explains that wildlife becomes endangered because natural habitats are being destroyed by human activities like cutting down forests. This loss of habitat pollutes animals' environments when humans use chemicals in agriculture. Hunting and poaching are also major threats, as hunters kill tigers and elephants for parts of their bodies like bones, fur, tusks, and teeth which are used for traditional medicine or carved into valuable objects. Overall, human activities are the primary reason for declining biodiversity according to Shawl.