For the first time in 23 years, a gray seal pup has been born at the National Zoo.

The zoo said Friday that the female pup was born Jan. 21 and is healthy, but is being hand-fed because her mother, Kara, is not producing enough milk.

“In the first days of this pup’s life, we did not see her gain as much weight as we would have expected,” said Ed Bronikowski, a senior curator, according to a statement issued by the zoo.

“It is still a tenuous time, but the pup’s weight is now heading in the right direction.” he said. “We celebrate every pound that she gains.” The pup weighs 44 pounds, up from the 35 pounds she weighed at birth.