Peter Crimmins

The four hatchlings are western Santa Cruz Island Galapagos tortoises. The Philadelphia Zoo's Lauren Augustine says there may be more on the way.

The four hatchlings are western Santa Cruz Island Galapagos tortoises. The Philadelphia Zoo's Lauren Augustine says there may be more on the way.

The parents are Abrazo and Mami, each approaching 100 years old. Mami has been in the Philadelphia Zoo for 93 years, captured wild in 1932. Augustine says that makes her genes extremely rare.

The parents are Abrazo and Mami, each approaching 100 years old. Mami has been in the Philadelphia Zoo for 93 years, captured wild in 1932. Augustine says that makes her genes extremely rare.

There are 44 western Santa Cruz tortoises in captivity and only a few hundred in the wild. For NPR News, I'm Peter Crimmins in Philadelphia.

There are 44 western Santa Cruz tortoises in captivity and only a few hundred in the wild. For NPR News, I'm Peter Crimmins in Philadelphia.