BUENOS AIRES (Reuters) - Three rare white tiger cubs delighted visitors at the Buenos Aires zoo on Thursday, tumbling in the grass of their enclosure in their first public appearance since being born late last year. Zookeepers said the birth of the blue-eyed Bengal tiger triplets represented an important contribution to saving the animals from extinction. "There are only about 250, not even 300, animals of this variety in captivity, so every birth in the Buenos Aires zoo contributes to saving this type of Bengal tiger," chief veterinarian Miguel Rivolta told Reuters Television. Rivolta said the zoo's breeding record showed...