Geoffrey Baer solves the mystery of a viewer’s “vague memory” from the 1940s, revisits an exhibit at the Century of Progress and opens the door to the Evanston History Center.

The newborn female Bornean orangutan joins five other orangutans living at the Brookfield Zoo.

What happens when a lion gets a toothache? Meet the large and dedicated team that cares for more than 3,000 animals at Brookfield Zoo. 

On Thursday, World Rhino Day, the zoo donated a piece of horn from one of its black rhinos to the U.S. Fish and Wildlife Service. The agency will use the sample to train its canine unit that sniffs out contraband at O’Hare International Airport.

Thanks to an experimental program started by the U.S. Fish and Wildlife Service in 2009, a wild population of threatened turtles has been established in northwestern Illinois. Find out how local institutions helped the agency reach its goal.

Two Chicago-area institutions are the first in the nation to receive certification in a new program that assesses the well-being of animals held in captivity.

Two Mexican gray wolf pups born at Brookfield Zoo last month were released into the Arizona wilderness as part of a carefully timed conservation effort. The species has been threatened by extinction for over half a century.

There's a new kid on the block at Brookfield Zoo. On Tuesday, a female zebra was born at the near west suburban zoo to mother Kali, 5, and father Nazim, 15. The birth marks the first addition of a zebra of this type at Brookfield Zoo since 1998.

Randall Wells, one of the world’s leading dolphin researchers, joins us to discuss the longest-running study of a wild dolphin population and his commitment to conservation. Read an interview and view a slideshow.

We share what you had to say about Cook County Board President Toni Preckwinkle and a recent giraffe birth at Brookfield Zoo in tonight's Viewer Feedback.

Brookfield Zoo is standing tall today after the debut of the 59th baby giraffe born on its grounds. At 5-foot-9 and 173 pounds, the calf was born 11 days ago to first-time mom Jasiri, and dad Hasani. Watch a web extra video of the giraffe's birth.

Need some ideas for what to do this weekend? Chicago Tonight knows what is going on!

Need some ideas for what to do this weekend? Chicago Tonight knows what is going on!

We show you how researchers are tracking cancer rates in the endangered Mexican Gray Wolf in tonight's Scientific Chicago.

What makes the Brookfield Zoo's science fair different from others?  We take a closer look at these students and their scientific savvy.

Need some ideas for what to do this weekend? Chicago Tonight knows what is going on!