To an outsider, it didn’t look unusual. As two keepers stood still inside the Forest & Wetlands habitat at Northwest Trek, they watched an old beaver slowly make his way into the pool. Sniffing everywhere, he walked slowly but steadily. Then he swam with front paws and whiskers outstretched to feel for the underwater entrance to his lodge before slipping inside. “There you go!” called one keeper encouragingly. R.B. Beaver, affectionately known as “Papa” for his role in the Northwest Trek beaver family, had just successfully shown that he could live a comfortable, capable life – without his eyesight. Eye …