Zoo Knoxville is celebrating the Earth Day birth of six critically endangered red wolf pups.
The pups were born to first-time mother Cirilla and nine-year-old Buckeye as part of a national breeding program.
Red wolves are the most endangered wolf species in the world, with only about 20 remaining in the wild and fewer than 300 in managed care.
The carefully planned pairing was part of the AZA’s Red Wolf Species Survival Plan to protect genetic diversity. Zoo officials say every birth is vital to the species’ survival.