Diana places a one-way mirror inside the observation window to test the dolphins.
So now, we're looking through a window and they'll be seeing a mirror.
Dolphins don't behave like this, staying in one place and staring, if they simply meet another dolphin.
This suggests they understand that what they're seeing isn't another animal but a reflection of themselves.
One action never normally seen is this curious fin wiggling.
It's an example of what scientists call self-directed behavior.
Things the dolphins only do when they're looking at the mirror.
Other self-directed behaviors included looking inside their mouths and twisting to see their belly.
They are using the mirror like a tool to look at parts of their own bodies they usually can't see.
This looks nothing like what they do when they're socially interacting with another.
They perform all sorts of odd behaviors much like we might do in front of the mirror, to see what we look like when we do that new dance step or when we just want to see how we look in a new in a new outfit or what we look like when we do a certain behavior.