Belgium's Antwerp Zoo has posted a sign outside the chimp house asking visitors not to stare at the animals. Apparently, continued interaction with humans, through direct eye contact for example, is distracting one particular chimp named Cheeta from bonding with the others. From the Associated Press:
(Zoo spokeswoman Ilse Segers) said that Cheetah's continued interaction with humans was "delaying the social integration of the animal in the group," and isolating the ape from the others.
A sign posted on the glass enclosure requests onlookers not to stare at the apes. "Look away when an animal seeks to make contact with you, or take a step back," said the sign. "Some individuals are more interested with visitors than their own kind."