BROWNSVILLE, Texas (ValleyCentral) — The Gladys Porter Zoo announced the historic hatching of six endangered Mangshan pit vipers.

The zoo has been working with Mangshan pit vipers for over a decade, but the hatching comes as the first greeting of the species at the zoo.

Gladys Porter Zoo is one of three institutions in the United States to successfully breed and hatch the endangered species.

“They are considered, by some, to be the rarest snake in the whole world,” said Clint Guadiana, curator of Herpetology at Gladys Porter Zoo.

There are about 500 Mangshan pit vipers snakes left in the world.

The newly hatched snakes are held off for exhibit until further notice. Parents of the hatchlings are on display for the public to see.