A hierarchical tree chart displays animal classifications from a root node through mammals, reptiles, and birds to leaf nodes like primates and snakes. Built with D3 v5 in a React application, the visualization uses `d3.hierarchy` and `d3.tree` to compute node positions. Each node appears as a circle with size proportional to its value, colored by type and level properties, while curved paths connect parent-child relationships. SVG rendering with custom stroke and fill attributes highlights the taxonomic structure.