Mama grizzlies mate later than other bears. They have two cubs instead of four. They wait four years – about twice as long as other bears – between having cubs. And after they’re pregnant, if winter is hard or their health is not good or the food supply is uncertain, they re-absorb the embryo into their body.
As people flock to urban centers where ground space is limited, cities with green walls and roofs and skyscraper farms offer improved health and well-being, renewable resources, reliable food supply, and relief to the environment.