The four lion cubs born at the National Zoo Aug. 31 had their first physical exam today. All four cubs are believed to be female, according to the vets, but it is difficult to determine their gender with certainty at such a young age. Each cub weighs between 7 and 8 pounds.

“They were great first-time patients and all four cubs appear to be healthy at this time,” said Dr. Katharine Hope, associate veterinarian at the Zoo. “Their eyes are starting to focus on things, their hearts and lungs sound clear, they are all strong and in good body condition and it looks like some of their lower teeth will start erupting soon.”

“The exam today was encouraging,” said Craig Saffoe, interim curator of the Zoo’s Great Cats Exhibit. “Shera has taken excellent care of her cubs since they were born, and we’ll provide the best care that we can to ensure that mom and cubs continue to thrive.”

Because the cubs are only 2½ weeks old, animal care staff members are cautiously optimistic. The mortality rate for cubs younger than 1 year old in captivity in 2009 was about 30 percent, compared to a 67 percent mortality rate for cubs in the wild. Their next exam will be in about a month, when staff will be able to confirm the cubs’ genders and administer vaccinations.

The Zoo’s other female, Nababiep (Shera’s 6-year-old sister), is expected to give birth. Luke, the 4-year-old male African lion, bred with both females earlier this year.