How do we know this belongs to a Tyrannosaurus? We know, because according to the latest scientific knowledge, there was no other meat-eating animal that could have produced this much excrement in Saskatchewan, Canada, where this fecal matter was found.
This is so far the only fossilized feces of a Tyrannosaurus rex that exists in the world.
The feces contain small fragments that look like bones from plant-eating dinosaurs. This means that Tyrannosaurus probably crunched down rather than tore the meat off the bones when it was devouring these plant-eating dinosaurs.