Seeing Green

Mangshan vipers are venomous snakes from high elevations in the mountains of southern China. The species was only recently discovered in late 1989, and recent surveys have shown it to be almost extinct in the wild. Accordingly, it has achieved the dubious distinction of being assigned “Endangered” status by the International Union for the Conservation of Nature (IUCN).

Affectionately called “Mangs” by the professional keepers that care for them, they are majestic serpents that grow to an impressive length of over seven feet! Despite their large size, Mangs are great climbers. They often lay in ambush within trees and shrubs, waiting for an unsuspecting bird or small rodent. Their brilliant emerald color, accented with browns and dark greens, perfectly provide them with the camouflage needed to blend into their moss-covered montane environment. Their faces are equipped with heat-sensory pits that allow them to detect the heat signature of a warm-blooded animal . . . even in complete darkness.

The Gladys Porter Zoo originally acquired a sub-adult female in 2009, and then a male in 2011. Once the pair was of breeding size, they were put together with the hopes of reproduction, but there was very little action for the first few years. In 2017, San Diego Zoo was the first U.S. institution to produce a verified captive-bred offspring. This got the herpetoculture realm buzzing with excitement that successful reproduction of this species was indeed possible! What we learned, however, was that they are not an easy species to breed outside of their uncommonly chilly montane natural environment. After multiple failed attempts to breed the pair at Gladys Porter Zoo, it was obvious something different had to happen if there was to be success.

One requirement for getting Mangs to breed was the ability to seriously cool them down during the winter. This was not easily done within their exhibit at the Herpetarium. In 2017, thanks to funds raised at Zoofari, the Zoo’s annual fundraiser, part of the proceeds were dedicated to the purchase of a custom refrigeration unit for the Mang exhibit. Starting in early November of that year, the snakes were cooled down gradually until the low was at 55 degrees Fahrenheit. After about a month of chilling, the exhibit’s temperatures were slowly brought back up into the 70s for spring.

The vipers were never observed to have bred, but the Herpetarium staff still hoped for the best. Well, they hoped for four-plus years, with no positive results, and optimism began to fade. In 2019, with the intention to offer more mate selection options, the Zoo acquired another pair of Mangs. These were placed with us on loan from the Animal World and Snake Farm Zoo in New Braunfels, Texas.

Offering a more dynamic group setting seemed to illicit some changes in behaviors. Finally, in October, 2021, one of the pairs were seen breeding! They were once again cooled down for the winter and in April 2022, the female looked larger than usual. Additionally, she started basking under her heat lamp – a great sign that she might be developing eggs. In time, she was separated from the group to give her some privacy. About a month later she laid a clutch of 22 eggs!

However, only six eggs appeared fertile. After 55 days of incubation, the first Mangshan viper baby emerged! The other five siblings emerged from their eggs over the next couple of days.

This breeding success at Gladys Porter Zoo marks only the third time the endangered Mang has been produced in a U.S. zoo. Though it took twelve years of vigilance and trial-and-error, the victory was “oh so sweet” for the entire Herpetology staff.