The trail leads deep into a Southeast Asian tropical rain forest, a steamy jungle with lush vegetation that closes in around us. We brush aside the dangling vines and peer through the trees for any signs of life.
From the distance white-cheeked gibbons approach, swinging through the treetops. A silvered leaf monkey perched on high cuddles her tiny youngster, whose bright orange fur makes him easy to see if the troop must flee.
In a nearby mangrove swamp, a family of proboscis monkeys is busily playing, arguing, resting and tending their young at water's edge. The fallen tree along the trail is hollow but not empty -- a python is coiled silently inside.
Before we leave this jungle setting, we'll encounter giant dragon lizards warming themselves on the rocks. We'll pass pools teeming with narrow-snouted crocodiles called gharials and listen to the eerie call of the black leopards. Then we'll walk through the door and out of the jungle into the next "zoogeographic" zone at the Bronx Zoo in New York City.
This JungleWorld is one of the finest indoor zoological exhibits to be found -- a state-of-the-art, naturalistic simulation of an environment where animals can live and breed much as they would in the wild.
JungleWorld, which can be enjoyed year-round, is one of several exhibits in the zoo's Wild Asia Complex. From May through October, an outdoor monorail carries visitors on a safari into the dark forests and open meadows of Asia in search of elephants, rhinoceroses, sika deer, antelope and Siberian tigers.
The Bronx Zoo has been called one of the best in the country, and perhaps the world. It is also the nation's largest urban zoo, where more than 4,000 animals -- many of them endangered -- live in a quiet 265-acre park surrounded by the busy streets of the Bronx. It is internationally recognized for its innovative exhibits, which invite visitors into a world where the animals do not live behind bars.
The zoo is operated by the New York Zoological Society, which also directs Wildlife Conservation International -- one of the premier conservation organizations in the world. And the zoo itself is active in species survival efforts and is noted for its successful breeding of animals in captivity.
Its proboscis monkeys are members of the species' only captive breeding family in the Western Hemisphere. The zoo has also had successful births of lowland gorillas, snow leopards, slow lorises and American bison. It is even studying the nesting habits the endangered white-naped crane to gather information to help preserve the species. A computerized "telemetric" egg has been placed in the nest to take readings of temperature and how often the egg is turned.
As part of its mission, the zoo tries to educate the public about the urgency of wildlife conservation and to encourage its support for these efforts. In the Zoo Center, for instance, graphic displays tell of a deadly trade in horns and tusks, which threatens the survival of rhinoceroses and elephants.
The story becomes more personal with a visit to the animals who live in this historic building, which dates to 1908. First, there's Rapunzel, a Sumatran rhino who was rescued from the wild as an orphan, nursed back to health and brought to live in the Bronx Zoo several years ago. She is one of only four hairy rhinos in the United States and part of an emergency breeding program to preserve her species.
Next door are Tus and little Sammy, who munch on hay, pausing from time to time to show affection for one another as only elephants can -- with their trunks. The massive 40-year-old matriarch of the Bronx Zoo herd and her adopted 4-year-old son stand side by side with trunks entwined in an elephant embrace.
It is the experience of seeing the wildness and beauty of animals, especially those living in a naturalistic setting, that makes the most persuasive argument for saving them.
The gelada baboons living in the Ethiopian highlands habitat are an outspoken bunch. There are two troops in the zoo's Baboon Reserve, and they have an extensive vocabulary, numbering more than 25 calls. They also communicate through behavior.
One recent rainy afternoon, several baboons sat grooming themselves on the other side of an observation window. A lone visitor approached, placed a hand on the window and made eye contact with them. Two reacted excitedly, jumping toward the window, baring their teeth in a wide-mouthed "smile" and staring right back at the visitor. A nearby graphic display interpreted their behavior as aggressive.
There are quieter animals living in the high passes and remote mountaintops of the Himalayan highlands habitat. A charming little red panda climbs about on a tree branch that was pruned back so he couldn't leave the exhibit to join his zoo visitors.