Tiger triplets were born at the Columbus Zoo and Aquarium on Tuesday, with all of them turning out to be male. The Amur tigers only weighed 2.5 pounds at birth.

Officials at the zoo said the triplets’ mother, Irisa, 10, didn’t nurse them, so staffers took over to hand rear them. They’re currently in an incubator in the Animal Health Center at the zoo.

President/CEO of the Columbus Zoo, Tom Stalf, said in a statement, “We are always cautiously optimistic about the survival of fragile newborns. But the cubs seem to be thriving under the 24-hour care provided by our animal specialists and veterinarians,” Delaware Gazette reports.

As of now, visitors aren’t able to see the cubs until they stabilize but the Columbus Zoo’s Facebook page posted some photos of the triplets.

“Initially, they were monitored using a remote feed from their den. However, the decision was made to hand rear them after Irisa failed to nurse them. This birth comes as great news for the Amur tiger, as the species is critically endangered with fewer than 400 left in the Russian Far East,” zoo officials wrote.

Baby animal alert! A trio of tigers were born yesterday morning to first-time mom, Irisa. The cubs weigh only 2.5 pounds...

Posted by The Columbus Zoo and Aquarium on Wednesday, April 22, 2015

image via Facebook from Columbus Zoo