[MARMAM] New paper on object manipulation using water flow in captive dolphins

山本知里 kurousagi0914 at gmail.com
Wed Oct 1 18:53:16 PDT 2014

Dear MARMAM subscribers,

I'm pleased to announce the following paper on object manipulation
using water flow in captive dolphins:

Yamamoto C, Furuta K, Taki M, Morisaka T (2014) Captive bottlenose
dolphins (Tursiops truncatus) spontaneously using water flow to
manipulate object. PLos ONE 9 (9): e107796. doi:

[Abstract] Several terrestrial animals and delphinids manipulate
objects in a tactile manner, using parts of their bodies, such as
their mouths or hands. In this paper, we report that bottlenose
dolphins (Tursiops truncatus) manipulate objects not by direct bodily
contact, but by spontaneous water flow. Three of four dolphins at Suma
Aqualife Park performed object manipulation with food. The typical
sequence of object manipulation consisted of a three step procedure.
First, the dolphins released the object from the sides of their mouths
while assuming a head-down posture near the floor. They then
manipulated the object around their mouths and caught it. Finally,
they ceased to engage in their head-down posture and started to swim.
When the dolphins moved the object, they used the water current in the
pool or moved their head. These results showed that dolphins
manipulate objects using movements that do not directly involve
contact between a body part and the object. In the event the dolphins
dropped the object on the floor, they lifted it by making water flow
in one of three methods: opening and closing their mouths repeatedly,
moving their heads lengthwise, or making circular head motions. This
result suggests that bottlenose dolphins spontaneously change their
environment to manipulate objects. The reason why aquatic animals like
dolphins do object manipulation by changing their environment but
terrestrial animals do not may be that the viscosity of the aquatic
environment is much higher than it is in terrestrial environments.
This is the first report thus far of any non-human mammal engaging in
object manipulation using several methods to change their environment.

This is an open-access and everyone can download this paper from
the following site:


Please email me at "kurousagi0914 at gmail.com" if you have any trouble
to download it.

All the best,
Chisato Yamamoto

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