And look! It has grown wings! It must be close to maturing.
Young dragons are relatively defenseless. They are born with relatively soft scales, which are shed and replaced with harder ones as the hatchling matures. Once a hatchling’s wings grow in, it marks the beginning of maturation. At this point they are often capable of hunting on their own and are usually left alone by their mother.
Yveltal often stains himself red with dye made from crushed beetles. He claims it's to 'show off his heritage', which with his Royal Crimson grandfather few can complain about, but some suspect greater reason - particularly as he sometimes 'paints' black lines and tries to camouflage his legs. At this stage of disguise, he frequently circles the skies yelling things like 'Oblivion Wing!' and 'Dark Aura!'.
Besides this odd tendency, he also has taught himself to hunt with a wooden slingshot as opposed to tooth and claw, something even intelligent prey doesn't expect.