From the beaches of Rio and the wetlands of Pantanal to the deepest jungles of the Amazon, Brazil boasts some of the most diverse and deadly wildlife on the planet. Its snakes, spiders and scorpions are renowned as man-killers, black caiman stalk its waterways and new species of deadly killers continue to emerge from the once-pristine jungles. Now we're examining the tactics and weaponry used by Brazil's premier predators and revealing why humans can only ever be cautious visitors to these wild domains.