PBS | 8:00 pm

The two-part miniseries “Nature’s Miracle Orphans” opens with “Second Chances,” exploring efforts by rescue centers in Australia and Costa Rica to help young animals survive on their own. A koala named Danny receives 24-hour attention — and a teddy bear, which actually helps him build up strength for climbing — and baby sloth Newbie’s case of pneumonia is suspected to be linked to the stress caused by having lost her mother.