Firstly, we have a moral obligation to protect higher animals.
Higher animals, such as mammals and birds, are born with an advanced nervous system which can enable them to feel. Therefore, like humans, higher animals also have the right to live and not to suffer abuse.
Secondly, the fact that animals kill each other does not mean that humans can kill animals.
If a child has killed a man, you may forgive the child, because children may not be intelligent enough to know the difference between right and wrong. Similarly, animals should be forgiven for killing others, because animals have low intelligence and thus cannot understand that their behaviors bring suffering to other individuals. However, adult humans are intelligent enough to be able to understand other individuals’ feelings. Therefore, if an adult human has killed or abused a higher animal, this human is evil.
Thirdly, human beings must fight against the law of nature.
The natural law that allows the stronger ones to prey upon the weaker ones runs counter to human morality. If not, there would be no need to help the disadvantaged groups. The laws of nature are brutal, but human morality is empathetic. Human beings must fight against the brutality and prevent the killings. At least, human beings must protect all mammals and birds from being killed and from suffering abuse, because all mammals and birds have developed advanced nervous systems.