Pets and Mounts Thru Capturing Baby Mobs

I see juvenile/baby hyenas, wolves, gazelles, rhinos, etc. There isn’t much use for them except killing them for resources. I was wondering if they could be captured like thralls and require specific (maybe rare) resources to grow and nurture. They could either turn into your loyal pets or mounts. Maybe some pets/mounts will be rarer or harder to obtain than others. Any other suggestions?