Zoos evolved at a time when travel for most people was impractical. Nowadays, wildlife watchers can hop on a plane to Africa, Australia, or Costa Rica for photo safaris or even stay at home and catch nature documentaries on television and view live Web cams from the Internet. Evidence indicates that the zoo industry, which once boasted attendance of more than 142 million people each year, is of declining interest to a public that has become much more knowledgeable about the needs and behaviors of wild animals and aware of the toll that captivity takes on animals meant to roam free.

Stir Crazy

Extreme confinement, barren enclosures, and the lack of opportunity to make any choices in their daily lives lead to boredom and neurotic behavior. With nothing to do, animals in zoos sleep too much, eat too much, and exhibit behaviors that are rarely, if ever, seen in the wild. Primates eat and throw feces and engage in a behavior called "regurgitation and reingestion"—vomiting into their hands and then consuming the vomit. Wide-ranging animals like bears and big cats pace constantly. Marine mammals repeatedly swim the same repetitious pattern in their tanks. Primates and birds mutilate themselves, and chimpanzees and gorillas become overly aggressive. Hoofed animals lick fences and perform strange lip, neck, and tongue movements. Giraffes twist their necks, bending their head back and forth repeatedly. Elephants bob their heads and sway from side to side. Captive animals may show no interest in mating or, alternately, become obsessed with sex.

And fish suffer, too. A study conducted by the Captive Animals Protection Society found that 90 percent of fish in public aquariums show "stereotypic" (neurotic) behaviors, such as interacting with transparent boundaries, repeatedly raising their head above the surface of the water, spinning around an imaginary object, and frequently turning on one side and rubbing along the floor of the tank.

Some zoos even resort to administering mood-altering drugs, such as Prozac, to address the public's complaints about psychotic inmates.

Mad Dash for Freedom

It's not surprising when angry and frustrated animals locked in cages seek opportunities to escape their dreary lives in hopes of finding freedom. Two endangered red wolf pups escaped from New York's Ross Park Zoo in January 2005, and one was eventually found dead in a ravine outside the property. On Christmas Day 2004, a rare Francois Langur monkey went missing from the San Diego Zoo. When zoo officials tranquilized the monkey to recapture him from a nearby tree, he plummeted to the ground with nothing to break his fall. In October 2004, an orangutan escaped from the Chaffee Zoological Gardens of Fresno, and five wildebeests escaped from the Fort Wayne Children's Zoo in Indiana—two of the wildebeests were euthanized because of injuries sustained during their escape. In March 2004, a young gorilla named Jabari was shot dead at the Dallas Zoo after escaping from his cage. In April 2004, a squirrel monkey escaped Jacksonville Zoological Gardens.