Is Morality factual or a belief?

Here's my thinking:

It's the human moral code that killing is wrong (an example of our morality). Yet some animals do it all the time. Because they are carnivores. Lions kill deers and eat them. But some animals aren’t carnivores. Like Elephants, yet they still kill for self defense. If a Lion tries to attack the Elephant, there is no hesitation between each other. The Lion will kill for food, and the Elephant will kill for defense. But Humans feel hesitation to kill. Since it contradicts our moral code.
An example is that for a pregnant shark, there's many baby sharks in the womb that will kill each other until one baby shark remains. Humans consider this as strange, but it’s normal in nature. It’s normal for animals but not humans, because contradicts our moral beliefs.
There are no rules in survival. Ever since life was created on the Earth, the mindset of every single organism was to eat, drink, reproduce, and survive. But when Humans came, we became much more advanced and made morals and laws. We made it “strange” that killing is bad, even though animals do it everyday.

So is morality something we just created to become a civil species? Or is morality part of nature?

(Sorry if my thinking sounds weird or wrong)