A seal pup was born at the National Zoo for the first time in 23 years on January 21. But keepers have been hand feeding the newborn pup since shortly after her birth as she’s not gaining enough weight through nursing from her mother Kara alone.

“Our animal care team is always prepared to hand rear or hand feed an animal if they need to,” Ed Bronikowski, senior curator at the Zoo, said in a release. “In the first days of this pup’s life we did not see her gain as much weight as we would have expected. It is still a tenuous time, but the pup’s weight is now heading in the right direction. We celebrate every pound that she gains.”

The pup is being tube fed “six times each day with a special formula that mimics her mother’s milk” and weighs 44 pounds — up from 35 at her birth. The Zoo is “cautiously optimistic” she will join four adult gray seals and two harbor seals in the American Trail exhibit this spring. One of those seals, Kjya, was born at the Zoo in 1990.