In this photo by Miki Toda, white Bengal tiger cubs watch visitors at the Saitama Tobu zoo in Shiraoka, Japan, during their introduction to the public Thursday. Their mother, Cara, gave birth to four male cubs on Jan. 25, and the zoo had a trial public appearance to test the cubs' reactions before their grand debut next week. The four cubs were unsure of what to do but were often curious during their few hours on display. They climbed on their mother, mimicked her scratching a tree trunk and bit anything to relieve their itching baby teeth. They stared at the visitors behind the glass, sometimes snarling at them. Zookeeper Yasuhiro Shimo said the cubs are being fed on their mother's milk and raw meat. "Last time I helped out with it, I felt like they have gained so much strength, and these little kitties are turning into real tigers," he said. The cubs' coloring is a genetic anomaly in Bengal tigers, seen in about 250 captive cats worldwide and extremely rare in the wild.