Australia has lost more mammal species than any country on Earth — and two introduced animals are the primary cause. This data story uses five interactive visualisations to explore the scale of Australia's feral cat and fox crisis, track population declines across threatened species groups, and show why a growing network of predator-free havens offers genuine hope. Built in R using ggplot2, plotly, and crosstalk. Created for RMIT University MATH2270/2610 Data Visualisation Assignment 3 (2026).