So, apparently some folks have known about this for a long time, but I just came across a reference to orca gathering together several members of a pod who then swim, dive, and surge synchronously to produce a wave displacing several tons of water.

Why would they do that? Well, it turns out it’s a good way for orca to wash prey animals who rest on ice floes – mainly seals – off the safety of their floating islands and into the open water where the orca can eat them.

Here’s one video which culminates in three orca using the strategy:

 

However, there are others. I came across a 45 minute TV program that would be inconvenient to use in demonstrating the tactic. Still if you’re willing to scan through and find it, you can see five orca swimming, diving, & surging synchronously to form a massive wave. While synchronized action isn’t unusual in the animal kingdom (think of birds migrating in V formations or schools of fish turning in near-unison among other things), this involves not only planning, but very possibly also either communicating a plan to one’s companions or, even more spectacularly, a theory of mind where the means to communicate a plan are absent, but other orca recognize what one orca is attempting to achieve in the future, then thinking about how to enhance the success of that other animal’s plan. Thinking from that other animal’s perspective, if that’s what’s happening, is a stupendous intellectual feat.

It would not be the only time one can see theory of mind operating in non-human animals, but the operation of theory of mind is rare.

And yet, the thing that completely disarms me intellectually is the thought that in this instance, the very water in which they swim has probably been rendered into a tool, which would challenge the very definition of the word. Wikipedia’s discussion of tool use by animals has a brief discussion of the difficulties inherent in defining “tool”. The first example they present, though, is sufficient to the point:

The external employment of an unattached or manipulable attached environmental object to alter more efficiently the form, position, or condition of another object, another organism, or the user itself, when the user holds and directly manipulates the tool during or prior to use and is responsible for the proper and effective orientation of the tool.

Is the seawater an “environmental object” or the orca’s environment itself? I’m not sure, but this is an incredible bit of cooperative hunting a raises a great many questions about orca, their intelligence, and even the nature of tool use itself.