The Best Father's Day in D.C. (We Ain't Lion)

Primate staff are mourning the loss of Kyle, a 28-year-old male Bornean orangutan who died Jan. 10.

This year was filled with incredible and heartwarming stories about the animals and the people who care for them. Enjoy a look back at some of the amazing things that happened this year.

Reaching up to 10 feet (3 meters) long, arapaima are the largest freshwater fish in South America. Learn what else makes these animals unique.