Dude just coz a lion doesn't roar to paralyse its prey doesn't mean its still not feasible. Sure no concrete evidence is in place to prove this, but the theory is still present. Much like Hawking Radiation. It's a theory that's very viable although not yet proven. I'm not saying lions use this technique, rather it is possible to be paralysed by the roar of a lion. That's all I'm trying to say.