Here's why:
* Extinct: Saber-toothed tigers (Smilodons) have been extinct for thousands of years.
* No recordings: We have no recordings of their vocalizations.
* Similar animals: We can look at the vocalizations of similar modern animals, like big cats like lions and tigers, but there's no guarantee they would have sounded the same.
Some scientists believe their roars may have been deeper and more resonant than those of modern big cats, due to their larger body size and different skull structure.
Ultimately, the exact sound of a saber-toothed tiger remains a mystery!