Here is how I came to realize that "animal communication" was a "fact":
My wife, our 9-year-old son, and I were visiting a horse barn just before it opened to the public. I later learned that all the horses, 13 of them, had been lately bought from different stables and were still in the process of getting acquainted with each other.
While observing the horses in their outside enclosure, I notice at one point that one of them was rejected by the others every time she was getting close to them. It is then that I realized that they were all standing two together as a couple.
While I observed the mare approaching one of these couples after being rejected by another, I asked my wife to count them.
When she told "Thirteen." I had a profound insight "SHE'S ALONE!"
As soon as I had this insightful thought, she stops in her track, lifts her head high, looking at me intensely, immediately transforming herself into a beautiful animal― before she was walking piteously― and started running joyously towards me.
It is then that I begin to understand that animals are "implicate" (cf, Bohm's implicate/explicate order) with their "specific" reality, their niche--into which they live as we live in our body, without any "objective representations." While we "explicate" our inner and outer world in space and time, thus having to use "specific" channels of "objective" communication (languages).
For the last forty years+ (I'm getting old), I have been working in and out of the university system and, as an outsider of normal science, at explaining the essential difference between us and the rest of the universe in scientific terms.
At 77, after two general BA and one unspecialized MA in Zoo-Anthropo-Sociology, and as a physicist-at-heart, I am presently in the process of putting to paper my theory of everything, which will be a non-mathematical ToE) explaining animal communication, migration, and gravity on the same basis (sic), along with many other unexplained phenomena using quantum principles, e.g., wave/particles duality, entanglement and Bohm's implicate/explicate orders, among all the other misunderstood principles of quantum physics (sic again).
I will publish my Ph.D. dissertation soon, I hope, on Quora and Medium. Why Quora and Medium? Because it is a Ph.D. dissertation that has to be understood by all honest minds from 9 to 99. I've tried to reach six years old, but I gave up!... I'm no Einstein.