One creature or a whole habitat?
A favorite figure can join a world the child already owns. An assortment offers more characters but may need scenery and storage. Ask whether the child enjoys collecting species or telling stories with one companion before choosing the number of pieces.
Look at how the animal is handled
A soft companion, a rigid figure and a construction model serve different kinds of play. Check size, care instructions and manufacturer age guidance for the exact item. Do not infer that a realistic animal model is intended for bath use or outdoor weather.
Use the interest to choose a new format
For a child with many figures, an animal picture book, craft or puzzle can give the theme a new activity. Check whether they want that process, though: liking an animal does not necessarily mean enjoying a long build or a sewing project.