This egg appears to be entirely metal. Is it a machine or is it actually a real creature with organic materials?
It is believed that Mecha eggs are simply "charging" and are trying to absorb energy from their surrounding environment. There is no creature that needs time to "grow" inside the egg. This means that, once the egg has reached its optimal energy levels, it's fit to hatch to begin living for its programmed lifespan.
The Mecha is referred to by the Science and Research Center in Ark City as an "organic bot." It is technically not "alive" but is rather a metal robot enhanced by artificial intelligence. It feels like a real pet because the Science and Research Center programmed the AI based off data that they had gathered from human focus groups attempting to answer the question, "What is your ideal pet?"
The Mecha's average charge span is 10 years. Currently, there is no known way to recharge a "dormant" Mecha.