The red colobus monkey is one of the most endangered primates in the world. Found in West, East, and Central Africa, the once thriving species has been decimated by over-hunting. Josh Linder has devoted his career to studying and conserving these peaceful primates. Plus: A few months ago, Francesco Ferretti led an expedition to be the first to ever tag endangered great white sharks in the Mediterranean. While he and his crew didn’t end up tagging any sharks, they uncovered exciting new evidence of great white activity in the water.

Later in the show: The bald eagle has been the national bird of the United States since 1782. But only a few decades ago, it was on the brink of extinction. Bryan Watts has been monitoring the bald eagle population in the Chesapeake Bay for 30 years. He says the bald eagle is one of the biggest success stories in the history of conservation. And: In the small island-nation of Sri Lanka, elephants are sacred animals. But Sujan Henkanaththegedara says the rich and powerful are illegally capturing wild and critically endangered elephants to have as symbols of wealth.