Question

why are animals killed

Answer 1

for food for fun for selling for pet for labor for medicine for decoration for sun for ivory for oil etc

Answer 2

various animals are killed for various reasons, such as 
1. rhinoceros for there horns which are used to make various instruments.
2. elephant's teeth(ivory) for the preparation of various jewelleries(ivory)
3, Tiger, which are now considered to be as endangered species are killed in large numbers for meat and there skin for various house hold purposes.
and there are a lot of examples of animals which are killed for mankind purposes.
so the basic reasons for their killings are:- for meat, horns, skins, bones, hairs, etc...........
hope u liked my answer.