Chimps, War and Morality

How most people see chimps.

Most people think of chimps as cute, cuddly, near-humans, because they don't know much about chimp behavior.  For example, Jane Goodall, most famous of all chimp researchers, witnessed the following event in 1974.

A gang of male chimpanzees invaded their neighbors’ territory and attacked a male chimp sitting by himself in a tree. The intruders dragged the chimpanzee to the ground, pinned him down, and bit and hit him all over his body. The attack ended when one member of the gang threw a rock at the bleeding victim. The battered chimp was never seen again and presumably died from his injuries.

That lead to a 4-year-long "war" between the two tribes in which the aggressors killed all the other tribe's males, annexed their territory and took all their females. 

Since then, researchers have recorded territorial wars between chimp tribes in multiple locations, like Ngogo, Uganda.

Young male jumping on a recently-killed rival.

Enemy males will be held down, then bitten and battered to death. Females are usually let go, but their babies will be eaten.

Last year, the Ngogo chimps stopped patrolling the region and annexed it outright, increasing their home territory by 22 percent

The objective of the 10-year campaign was clearly to capture territory, the researchers concluded.

So, is this moral, or immoral behavior?  What if a group of men attacked another, killed all the men, ate the babies, took the women for sex and took their land?  Would that be moral, or immoral behavior?  What's the difference?