From Livescience.com: " Xiao Liwu, the charismatic panda cub born at the San Diego Zoo last year, celebrated his first birthday today with a towering three-tiered "cake" made from ice and bamboo, decked out with yams, apples, and shaved carrots. The giant panda cub, whose name means "little gift," was born on July 29, 2102, the sixth offspring for mother Bai Yun. "Weighing a pound and a half [0.6 kg] when he was first examined 23 days after his birth, he is now just over 41 pounds [18.5 kg] of pure energy," the zoo said in a statement. "Affectionately called Mr. Wu by his keepers, he is described as a very smart and inquisitive cub whose favorite activities include roughhousing with his mom and napping in his favorite spot in one of the tallest trees on his exhibit," the zoo added. There are thought to be only 1,600 giant pandas left in the wild and their natural habitat is restricted to mountainous forests of China. Captive breeding is one way to study and conserve the endangered species, but these efforts are notoriously difficult, largely because pandas have a very narrow mating window. So far this year, U.S. zoos have welcomed two new baby pandas: twins born at Zoo Atlanta two weeks ago. All pandas in the United States technically belong to China, which loans the fuzzy creatures to foreign zoos." Follow Megan Gannon on Twitterand Google+. Follow us @livescience, Facebook& Google+. Original article on LiveScience.com.