When worms are treated with exogenous serotonin, their locomotion significantly decreases.30 Additionally, KIF13A conditional knockout mice have 5HT receptor trafficking defects resulting in anxiety as measured by an inability to perform certain behaviors.10 These links prompted us to ask if serotonin signaling was at the root of klp‐4 mutant locomotive defects. This evidence concerns the gene KIF13A and Anxiety.