The first indicator was the time of day. Although we do sometimes observe wolves out and active in the middle of the day. It is rare. Nine out of 10 days we are observing wolves only at the crack of dawn or at dusk. What really gave it away was when they stated that several of the canines wore radio collars and that a whip antenna was visible sticking up.
Coyotes are the only canine wearing radio collars with whip antenna's.
Radio collars attached to wolves do not have a visible antenna. Color and size are also both good indicators, although most lay people have a difficult time field judging weights and are unfamiliar with the color options with Rocky Mountain Grey wolves. Right this moment, in Yellowstone, the majority of wolves are black in color. The average weight on an adult Yellowstone wolf is about 124 pounds. Coyotes are in the 35 pound range, and only come in the grey color.