Heroic cat charges into large pack of dogs one of which was savaging another cat to save their life

We don't know the relationship between the cat who was grabbed by a dog who was a pack member and the lifesaving cat but this amazing cat charges at the dog with the other cat in its mouth and scatters the pack. The courage was enormous. It is probable that this cat is the mother of the young cat who was attacked and who would surely have died fairly quickly but for the intervention.

The main impression one gets from watching the video is courage and fearlessness. She dives in knowing that there was a strong risk of injury or death. She throws herself at the central dog who led the attack. Her forelegs are in front of her, claws out to smack the dog around the face. The dog releases the young cat. Both cats scram. 

The quality of the picture below (a screenshot) is hopeless but it is on the page to provide a 'featured image' for SEO purposes.

On the internet you will see a lot of videos and still images of mother cats defending their offspring. I can't be sure that's the case in this video but I feel that it is.

Do cats have a natural fear of dogs?

This is a social media question about domestic cats. Note that this is about domestic cats. Clearly a Bengal tiger is not going to be scared of a single medium-sized dog! Point made.

Neighbour's dogs repeatedly escape neighbour's yard and attacks a man's cats. This is neither the cat nor the dog in the story. Pic in public domain as assessed.

Domestic cats have a natural fear of predators of domestic cats. They know when they are about to be a victim of a predatory attack by any animal or human larger than them. This is not therefore limited to dogs.

So that ability is innate and natural. But it is not possible to say that all cats have a natural fear of dogs. It is wrong because if a cat has been socialised to domestic dogs at an early age, they will be friendly towards dogs all their lives. We see many examples of cats and dogs being friendly towards each other.

This is about size too as the domestic cat is a top predator. Small predators such as the domestic cat are vulnerable to larger predators. This holds true with respect to the small wild cats such as the caracal being attacked by the large wild cats such as the leopard. See below:

Leopard a large wild cat species and a top predator kills and eats a small feline predator the caracal. Image in public domain. 

A very small dog or puppy would at least be vulnerable to an attack by a large feral cat although an attack would be unlikely.

I think size matters. As dogs are almost invariably larger than domestic cats the attacker and the attacked will be dog and cat respectively.

But it could be the other way around. A tiger would kill a single wild dog with one swipe. There is no natural fear of dogs in a Bengal tiger unless we are referring to a large pack of wild dogs which can kill a tiger.

Conclusion: Do cats have a natural fear of dogs? No, just a natural fear of predators that they perceive as genuinely dangerous and posing a serious threat.