The San Francisco Zoo recently introduced its lemurs to some pink plastic flamingos. The results were predictably adorable, but the flamingos weren't just decoration. They're an effort to give the lemurs a bit of mental exercise.
Above: a ringtailed lemur inspects the plastic intruder.
While most zoos try to present animals in as naturalistic a setting as possible, several logistical challenges inherent to zoo life make this difficult for some species. In order to address these challenges, section 3 of the Animal Welfare Act requires that zoos in the United States provide social and environmental enrichment for non-human primates and dogs, though most zoos extend the mandate to cover most or all of the species housed in their institutions, where appropriate or feasible.
Thoughtfully designed environmental enrichment programs, it is thought, allow captive animals to display a wider variety of naturalistic behaviors. Plenty of scientific research has indicated that when animals exhibit their natural behaviors, zoo visitors have a better and more educational experience, and animal welfare is improved.
One form of environmental enrichment involves introducing new objects for the animals to explore. The novelty provides a bit of a mental workout, and the objects provide plenty of tactile stimulation as well. As a bonus, an animal's response to novelty is sometimes a good indicator of overall mental health: if an animal is fearful of a new object, that could indicate an excessive amount of stress. It is thought that more "optimistic" individuals are more likely to eagerly explore new objects.
A red ruffed lemur:
A black and white ruffed lemur:
A red fronted brown lemur: