Though the National Zoo had expected and prepared for a second black and rufous giant elephant-shrew birth in as many weeks, staff grew concerned when the giant elephant-shrew appeared outside its nest three days after it was born — nearly three weeks before it should have. Something was wrong. But on Sunday, before zoo staff could intervene, the baby elephant-shrew was killed by its mother. Elephant-shrews are altricial animals, meaning that the young require…