Two-day old cheetah cubs.

Admit it: It’s nearly impossible not to melt upon looking at the newest arrivals to the Smithsonian’s National Zoo. These two cheetah cubs are utterly adorable, but the story of how they arrived at the zoo is a bit harrowing.

In late April, the zoo’s 5-year-old cheetah, Ally, went into labor at the Smithsonian Conservation Biology Institute in Front Royal, Va. She gave birth to one cub, but then abandoned him to the cold weather while her labor stopped before three other cubs could be born, the Associated Press reports.

Veterinarians performed an emergency cesarean section procedure and were able to rescue one other cub, a female; the other two died.

For the first two weeks of their lives, the new cubs, who don’t yet have names, were raised by hand at the Front Royal facility. They were moved to the National Zoo earlier this month where zoologists will continue to raise them by hand. As evidenced by some of the photos, they’re feeding on bottles, but are also moving toward solid food—such as store-bought cat food—as they develop teeth, the AP reports.

But the tender, direct care zoo workers are giving these cubs—as well as the extraordinary measures taken during the birthing process—is entirely ordinary in a broad attempt by U.S. zoos to replenish cheetahs, which are threatened with extinction in the wild:

“It’s very rare and it’s very risky,” said cheetah biologist Adrienne Crosier. “We were certainly concerned about the welfare of the mother.”

When the female cub was born, she had a heartbeat but didn’t breathe on her own for several hours. Both cubs and mother were in intensive care for three days.

Because cheetahs are endangered, North American zoos are trying to build a self-sustaining population. It’s been estimated there are only 8,000 to 12,000 cheetahs left in the wild, Crosier said.”

The zoo says it’ll still be a few more months until the cubs are ready to join their fellow fast cats in the cheetah yard, but yesterday the zoo offered the first glimpses of these growing beasts.

So until they go on public display, enjoy.