For Taking. Use tranquilizing darts. I have an ascendant crossbow and kept killing them by accident. As it seems it takes a lot of tranq arrows take one down. But when using tranq darts it took couple shots but did trick.
The best spot to tame one is on the little island in the corner of the north biodome. Which pretty much is penguin island. Nothing really pops up there to bother you unless you count the ocean. Also dododex does say it has a high tampour drop, but if you have some raw prime meat on you it isn't going to be a problem. Tamed a lv110 it's only 5 pieces of raw prime.
They are so cute! I tamed one today and I named it Karri. She is a juvenile and very weak but still cute. If you kill baby or juvenile kairukus on purpose. I will find and burn your base in multiplayer.
DO NOT MAKE THE SAME MISTAKE AS I DID. I hit headshots when trying to knock this oversized penguin out, and it died... Just remember to go for the body, and only use tranq DARTs, otherwise it will die, please share to others