Edited by John G. Hildebrand, University of Arizona, Tucson, AZ, and approved October 16, 2020 (received for review August 12, 2020)Like many other animals, including humans, insects frequently move through densely cluttered environments to perform activities critical for their survival, such as foraging. Vertebrates avoid collisions by perceiving their surroundings in relation to their body size and form, but it is unknown whether insects, with much smaller brains, possess such skills. We discovered that flying bumblebees judge the gap between obstacles relative to their wingspan and...…Edited by John G. Hildebrand, University of Arizona, Tucson, AZ, and approved October 16, 2020 (received for review August 12, 2020)Like many other animals, including humans, insects frequently move through densely cluttered environments to perform activities critical for their survival, such as foraging. Vertebrates avoid collisions by perceiving their surroundings in relation to their body size and form, but it is unknown whether insects, with much smaller brains, possess such skills. We discovered that flying bumblebees judge the gap between obstacles relative to their wingspan and...WW…