Why are dogs afraid of fireworks?

Now that today is 4th of July and my four pawed pet darling is lying next to my feet since hours, makes me wonder: why are dogs afraid of fireworks?…From newborn pups to older dogs, all of them are scared of fireworks- more importantly the sound than the visual.

Now why do they do it? Why are dogs scared of explosive noises? There have been multiple hypotheses about this; some say it is because of that particular dog not being exposed. Some others say that dog might have been yelled at every time it was scared in the past at the sound. All pointing to the “nurture” aspect that the dog has or has not been. However, how about the “nature” aspect.

What if this is deeply ingrained in the DNA of all dogs from an event that occured millenia ago? Maybe an extinction like event? It was so catastrophic that it got embedded into the genes of the dogs then, warning the progeny that if you hear firework like explosions, run. That is how world is going to end.

I agree, definitely this can be categorized as a conspiracy theory, except I am not conspiring anything. LOL. But yeah, take care of your pups, whatever the root cause reason be.