if you have a snow owl, when doe is low health and starting defensive form, use snow owl heal him, when above a certain health level he will return to normal form and can fire arrows or tranquilizer continue (Sorry if my english is bad).
Doedicurus
The Doedicurus is an armored, armadillo-like herbivore prized for gathering and carrying stone. When threatened, it curls into a remarkably well-protected ball.
Player-written tips for taming, using, and fighting the Doedicurus in ARK: Survival Ascended & Evolved.