Researchers at Chicago's Field Museum collaborated with fragrance chemists to recreate what is likely the foul odor of a T. Rex's breath. Now, museum visitors can push a button for an olfactory experience of the dinosaur age. The new sensory station is part of an exhibit centered around the most complete T. Rex skeleton ever discovered. From Atlas Obscura:
They quickly gave up on imitating T. rex poop. Most of the commercially available synthetic feces scents are imitations of human waste, and our generally omnivorous diets stray too far from SUE's carnivory. Cat poop is slightly better, because they're obligate carnivores, (exhibit developer Meredith) Whitfield says, but hyena droppings would be ideal, because that includes both chewed-up meat and ground bones, just like SUE's deuces. Turns out synthetic hyena poop scent is hard to come by, so the team moved on. (But, Whitfield adds, "If you're at the hyena enclosure at the zoo and smell their poop, that's probably close to what T. rex poop smelled like.")
Dino breath, on the other hand, was both tempting and feasible. "From anatomical studies of SUE's teeth, we can say, 'Well, you have the kind of anatomy that might suggest that you have some nasty raw meat decaying in your mouth,'" Whitfield says. "What did that smell like? The answer is: Bad."
The team found a service that manufactures a range of prepackaged smells—mainly pleasant air fresheners for hotel lobbies and other benign places, but also stinky ones for police training exercises, so that officers can learn to detect stuff like meth labs, decomposing bodies, and other malodorous things. The one called "decaying flesh" fit the bill quite nicely—but the challenge for the design team was making sure the smell didn't clear the exhibit with its foulness or make visitors retch when they caught a whiff. "One of the variants was so bad that I said, 'This is probably really accurate, but I don't think we can expose visitors to this,'" Whitfield says.
