Asexual propagation (cloning) is a widespread reproductive strategy of plants and animals. Although larval cloning is well documented in echinoderms, identified stimuli for cloning are limited to those associated with conditions favorable for growth and reproduction. Our research shows that larvae of the sand dollar Dendraster excentricus also clone in response to cues from predators. Predator-induced clones were smaller than uncloned larvae, suggesting an advantage against visual predators. Our results offer another ecological context for asexual reproduction: rapid size reduction as a defense.