This interactive family tree visualizes animal classifications and their evolutionary relationships using a hierarchical tree layout. Users expand or collapse branches by clicking on nodes, with smooth 1.1-second transitions animating nodes and links to their updated positions. The code uses d3.layout.tree to position nodes, d3.svg.diagonal for curved connection paths, and d3.json to load the embedded data.json file containing taxonomic groupings. The SVG rendering includes custom node styling defined in CSS, with collapsed nodes distinguished by lightsteelblue fill.