Why Do Dolphins Carry Sponges?

• DOI: 10.1371/journal.pone.0003868
• Publication Date: 2008-12-09T23:53:35Z
• Authors: Janet Mann; Brooke L. Sargeant; Jana J. Watson-Capps; Quincy A. Gibson; Michael R. Heithaus; Richard C. Connor; Eric Patterson
• Keywords: Bottlenose dolphin

Tool use is rare in wild animals, but of widespread interest because its relationship to animal cognition, social learning and culture. Despite such attention, quantifying the costs benefits tool has been difficult, largely if occurs, all population members typically exhibit behavior. In Shark Bay, Australia, only a subset bottlenose dolphin uses marine sponges as tools, providing an opportunity assess both proximate ultimate document patterns transmission. We compared sponge-carrying (sponger) females non-sponge-carrying (non-sponger) show that spongers were more solitary, spent time deep water channel habitats, dived for longer durations, devoted foraging than non-spongers; and, even with these potential costs, calving success sponger was not significantly different from non-spongers. also clear female-bias ontogeny sponging. With solitary lifestyle, specialization, high demands, used tools any non-human animal. suggest ecological, social, developmental mechanisms involved likely (1) help explain intrapopulation variation female behaviour, (2) indicate tradeoffs (e.g., allocation) between ecological factors (3) constrain spread this innovation primarily vertical