Gestural communication among mammals is obvious but not a real test of the idea because we're deeply similar.
Better test: Cephalopods, who have tremendous intelligence and manipulative limbs but share very little genetic connection with us. You can find lots of videos of confrontations between humans and cuttlefish, or humans and octopuses. It's clear that each side understands the other's intentions to some extent.
The scientist's dream of math as universal language has never made sense. As Polistra noted earlier, you can develop the technology needed to signal or reach other planets without ever using symbolic math, so you can't assume that math must be the 'least common denominator' between critters on different planets. For fuck's sake, even humans within the same ethnic group and economic class and family don't use math to communicate! We use a mix of words and gestures.
When we do use math, it's always for the exact opposite purpose: to establish our membership in a mysterious priesthood that owns specialized secrets. Math says "I know things you don't know, and I'm going to prevent you from learning. Nyah nyah nyah."Labels: Danbo
The current icon shows Polistra using a Personal Equation Machine.