Idk if anyone has experienced this before on Mobile, but for some reason every time you shoot a pheromone dart at a creature and then hit it, the megaloceros will target you instead and attack you even though they are non-aggresive. Idk if its a bug in the game or is an actual mechanic in the game
They're found in red woods and at the snow biome. Make sure to take precaution when approaching as these biomes are pure danger. I recommend to have a small perimeter around it to keep it from running away and keep most carnivores out.