Unknown to Slobodchikoff, around the same time that he began recording prairie-dog alarm calls in Flagstaff, Peter Marler, the renowned animal-communication expert
and one of Slobodchikoff’s former professors, was working on a similar study, one that would eventually redefine the field.
In one experiment, black-tailed prairie dogs — one of the five prairie-dog species in North America — distinguished human trespassers by height
and T-shirt color and further produced a signature call for a person who repeatedly fired a 12-gauge shotgun into the ground.
Slobodchikoff arranged for various dogs — a husky, a golden retriever, a Dalmatian
and a cocker spaniel — to wander through a prairie-dog colony one at a time.
Instead of relying on a fixed repertory of alarm calls, they were modifying their exclamations
in the moment to create something new — a hallmark of language Hockett called “productivity.”
By the late 1990s, Slobodchikoff had transitioned from studying paper sonograms to generating computer-based
statistical analyses of the frequency, duration and harmonic structure of prairie-dog vocalizations.
Prairie-dog communication is so complex, Slobodchikoff says — so expressive and rich in information — that it constitutes nothing less than language.
In lieu of a precise definition for language, many experts and textbooks fall back on the work of the American linguist Charles Hockett, who in the 1950s and ’60s proposed a set of more than a dozen “design features”
that characterize language, like semanticity — distinct sounds and symbols with specific meanings — and displacement, the ability to speak of things outside your immediate environment.
If Slobodchikoff is right about their language — to say nothing of all the other undeciphered clucks, yawps and bellows on Earth — then we will have been the cause of, and the indifferent witness to, the annihilation of a species
that helped transform our understanding of animal minds.
