Rarotonga, Cook Islands

From the Cook Islands in the South Pacific. This was sent from the largest and and most populated island of Rarotonga. The stamps are a 2016 WWF issue featuring manta rays and they actually say "Raotonga" on them as well as "Cook Islands". Stamps are issued for all three of the main islands : Rarotonga, Aitutaki and Penrhyn, but there are also Cook Island stamps. As I understand it they are all produced by the same entity (I could easily be wrong about that) and I imagine this is done to sell more stamps to collectors. Why else would a county of 20,000 need so many postage stamps.