Walrus shed their tusks frequently and both male and female have tusks. No animals are killed for tusks.
That may be true for walruses, but not elephants. Ivory is a status symbol in Japan and they will pay big bucks for it.
One solution they came up with was that after some elephants were being shot multiple times for their tusks, they came up with a plan to sedate the animals and cut the tusks off. It made it more difficult for the animals to defend themselves, but at least they would be alive.