The Smithsonian’s National Zoo released photos today of a pair of Andean bear cubs born last December. The cubs, a zoo press release reads, appear to be “healthy and thriving” following an examination earlier today in which veterinarians gave them thorough check-ups.

Zoo staff members inspected the bears’ hearts, lungs, mouths, eyes, legs, feet, and genitals. However, while the two-month-old cubs are still not developed enough to precisely determine their genders, the zoo is ready to make an educated guess.

“Although it is difficult to determine the sex at such a young age when genitalia have not fully developed, the cubs appear to be male and female,” the press release reads. One cub weighs 10.1 pounds, slightly heavier than its 9.2-pound sibling.

The cubs were born December 13 to Billie Jean, a six-year-old female Andean bear that previously gave birth to a pair of cubs in 2010. (One still resides at the National Zoo, the other has since been moved to a park in Tulsa, Okla.) Since the cubs were born, the bears have been removed from public display but have been seen on the National Zoo’s “bear cam.” They are scheduled to go back on view in the spring.

Andean bears—also known as spectacled bears—are listed as a threatened species by the International Union for Conservation. It is estimated only 2,000 remain in their natural habitat in northwestern South America.