日前，费城动物园一只雄性大猩猩为避免弄脏双手，竟然选择直立行走。
A male gorilla at the Philadelphia Zoo is taking a stand against dirty hands by opting to walk on two legs.
显然，18岁的路易斯是个有洁癖的猩猩。
Apparently, 18-year-old Louis is a clean freak.
当路易斯的双手满是西红柿或其他零食时，他就像人类一样直立行走，来保持食物和双手的清洁，而不是以典型的大猩猩姿势--身体前倾，撑在指关节上行走。
When Louis has his hands full of tomatoes or other snacks, he walks upright like a human to keep food and hands clean, rather than the typical gorilla stance of leaning forward on his knuckles.
灵长类动物和小型哺乳动物园区管理人迈克尔·斯特恩表示，工人们必须在院子里的泥坑安装了一条消防水带。
Michael Stern, curator of primates and small mammals, says workers had to install a fire hose over a mud puddle in the yard.
这只近500磅、6英尺高的灵长类动物，为了避免弄脏自己，会小心翼翼地穿过去。
The nearly 500-pound, 6-foot-tall primate crosses it like a tightrope to avoid getting dirty.
斯特恩称，大猩猩直立行走“非常罕见”。在野外，像路易斯这样的西部低地大猩猩，可能会为了取食物或涉入沼泽地，而直立行走几秒钟。
Stern says it's "pretty unusual" for gorillas to walk around upright. In the wild, Western lowland gorillas like Louis might do it for a few seconds to reach food or wade into swamps.