I recently had the pleasure of visiting one of the most advanced and impressive zoo I've been to, the Copenhagen Zoo. In overall appearance and plan it reminded me very much of the Bronx Zoo, where I worked for a short time. In fact it was so similar I have no doubt many of the same people were involved in planning the individual habitats in the two zoos. The two are so similar that I could say to my wife, "this looks just like the place in the Bronx Zoo where they have the crocodiles and river turtles," only to turn the corner and find the crocodiles and river turtles in nearly identical enclosures.
Almost all of the enclosures were state of the art, made to look and feel as much as possible like habitat, with places the animals can go to get out of the weather, and out of the view of tourists, or where they lay in the sun if they so choose. They had a large display (in Danish, so I couldn't read any of it) on the bad old way of doing thing, set up so that the viewers actually walk through a series of cold cement cages with giant steel bars where rhinos and hippos used to be kept. But what impressed me most was the attention paid to making sure the animals had something to do. The anteater ate not from a trough, but from a rotten log with numerous holes drilled in it and food stuffed into each hole. This gave it something to do with its improbably long tongue and impressive curved claws. Rather than laying around looking bored, it spent its time ripping open logs and licking food out from inside them.
Inside the impressive new elephant house the elephant also has to work for its food. I spent half an hour watching an elephant attempting to extract its food from a large barrel hung 5 meters off the ground. The barrel hangs from a rope, such that the elephant can barely reach it with its trunk. By repeatedly whacking the barrel with the tip of its trunk it can make it swing enough that eventually some of the food inside spills out on the ground. The elephant then eats this and goes back to whacking the barrel. By the time the meal was over, the elephant looked honestly tired, a rare and precious thing for a zoo animal.
The bears spent enough time digging in their enclosures (with enough magpies and starlings closely following them) that I can only assume there was food buried somewhere in there, with the location changing from day to day. Over and over throughout the zoo we saw animals doing something.
The term in the zoo community for this is behavioral enrichment, and it turns out to be incredibly important not only for the animal's mental state, but for their overall health, their longevity and the satisfaction and education of the viewing public. Crowds these days don't just want to see an elephant standing there, they want the elephant to be happy, and they want it to be doing something. In the Copenhagen Zoo, the animals are doing something, and usually it is something similar to an actual behavior observed from the wild. Wild elephants really do whack and grab overhead food with their trunks. Anteaters really do tear open rotten logs. Behavioral enrichment takes a lot more thought, and a lot more work, than dumping food in a trough, but it makes for a wonderful zoo. (A recent episode of the NPR show Radio Lab focuses on Zoos, and talks a lot about the importance of behavioral enrichment.)
We spent about eight hours walking around the Copenhagen Zoo, and saw most but not all of it. I strongly recommend it to anyone who loves animals, whether or not you love zoos. I took about 500 pictures that day, 60 of the better ones are linked to below.