The Conical Sponge (Echinodictyum mesenterinum) is a species of sponges in the family Raspailiidae.
A community of Indo-Pacific bottlenose dolphins in Shark Bay, Western Australia, made up of approximately 41-54 animals, are known to use conical sponges as tools while foraging. This behavior, termed "sponging", occurs when a dolphin breaks off a sponge and wears it over its rostrum while foraging on the seafloor. Sponging behavior typically begins in the second year of life. During sponging, dolphins mainly target fish that lack swim bladders and burrow in the substrate. Therefore, the sponge may be used to protect their rostrums as they forage in a niche where echolocation and vision are less effective hunting techniques. Dolphins tend to carry the same sponge for multiple surfacings but sometimes change sponges. Spongers typically are more solitary, take deeper dives, and spend more time foraging than non-spongers. Despite these costs, spongers have similar calving success to non-spongers.
There is evidence that both ecological and cultural factors predict which dolphins use sponges as tools. Sponging occurs more frequently in areas with higher distribution of sponges, which tends to occur in deeper water channels. Sponging is heavily sex-biased to females Genetic analyses suggest that all spongers are descendants of a single matriline, suggesting cultural transmission of the use of sponges as tools. Sponging may be socially learned from mother to offspring. Social grouping behavior suggests homophily (the tendency to associate with similar others) among dolphins that share socially learned skills such as sponge tool use. Sponging has only been observed in Shark Bay.