Do whales use tools?
This week, a video was swirling around several social media in which a male dolphin could be seen bringing a sponge to a female. This curious behaviour has raised many questions not only amongst scientists, but the general public as well. Is this the only way that whales use tools?
A few studies have examined the use of tools in dolphins in their natural habitat. There are a multitude of reasons that might motivate a dolphin to use something other than its own body in different situations such as breeding or feeding.
From what we can gather in this video that has gone viral, a male dolphin wants to court a female. For him, using a sponge might be a means of expressing his reproductive instinct. Indeed, Australian humpback dolphins (Sousa sahulensis), “present marine sponges [to females] and engage in physical posturing and acoustic displays,” explain Allen and his team in an article published in October 2017 in the scientific journal Nature. This study reveals that Australian humpback dolphins offer sponges for breeding purposes rather than for playing or feeding, since only males behave this way. Males therefore swim from female to female to offer this sort of “gift”, but only to those that are sexually mature.
Some dolphins can also use sponges to forage for food. Both males and females have been observed with sponges in their mouths. Since it cannot keep the sponge in its mouth while hunting prey, the dolphin only uses it to make foraging easier. According to Mann and her team, “Tool use with marine sponges is clearly a foraging behaviour that involves using the sponge to ferret prey from the sea floor.” The technique is used in some very specific dolphin populations, all located in Shark Bay, Australia. The use of tools by foraging cetaceans was first observed in the mid-1990s (Hans Thewissen).
Tool use in aquatic animals is quite rare in nature. Some animals use objects for foraging or for reproduction. In other animals, researchers have not yet pinpointed any specific use for these items. It could be for playing or even for mourning, as in this video of a beluga rolling a piece of wood over its back.
(2011) Allen, S.J., L. Bejder and M. Krützen. Why do Indo-Pacifc bottlenose dolphins (Tursiops sp.) carry conch shells (Turbinella sp.) in Shark Bay, Western Australia? Mar. Mammal Sci. 27, 449–454
(2017) Allen, S.J., S.L. King, M. Krützen and A.M. Brown. Multi-modal sexual displays in Australian humpback dolphins. Scientific Reports. Nature.
(2008) Mann, J. et al. Why Do Dolphins Carry Sponges? PLoS ONE 3.
(2009) Perrin, W.F., B. Würsig and J.G.M. Thewissen. Encyclopedia of Marine Mammals. Academic Press: 395.
Stéphanie Tremblay, with her insatiable appetite for science, joined the GREMM team this year as part of her professional writing internship. A passionate writer, she contributes to Whales Online. With the tips of her fingers, she takes you into Quebec’s world of cetaceans and guides you through a vast ocean of topics.