A tree visualization displays hierarchical animal data with D3.js, using a static dataset defined in JavaScript. The code builds an SVG-based dendrogram through `d3.tree()` and `d3.hierarchy()`, positioning nodes and links with horizontal link paths. Circles represent each animal, with text labels arranged by parent or leaf status. Interactive hover animations via `transition` enlarge circles and change their fill color, while the stylesheet controls node and link appearance.