•Structural heterogeneity is more influential for animal diversity than is simple canopy cover.•Taxonomic groups respond to different components of 3D ecosystem structure.•Biases in the literature preclude syntheses for some taxonomic groups and regions.•LiDAR has tremendous potential to further advance understanding of animal ecology. The advent and recent advances of Light Detection and Ranging (LiDAR) have enabled accurate measurement of 3D ecosystem structure. Here, we review insights gained through the application of LiDAR to animal ecology studies, revealing the fundamental importance of structure for animals. Structural heterogeneity is most conducive to increased animal richness and abundance, and increased complexity of vertical vegetation structure is more positively influential compared with traditionally measured canopy cover, which produces mixed results. However, different taxonomic groups interact with a variety of 3D canopy traits and some groups with 3D topography. To develop a better understanding of animal dynamics, future studies will benefit from considering 3D habitat effects in a wider variety of ecosystems and with more taxa.