Nowadays this world is very quickly changing, changing. In 1945 there were only 2 billion human beings. It took many thousand years of history to produce this number of people.
Human beings like to eat meat, also kill many animals.
Nowadays with all kinds of advanced technology, human beings have been killing many many more animals than before. But no animal likes to die. Animal mind means strong like-dislike. Also each kind of animal only understands its own kind, so animals form groups. So nowaday human beings are just like that.