When an endangered species becomes so imperiled that extinction seems imminent, scientists may have no choice but to collect the last wild individuals and create a captive breeding program. Condors in California, red wolves in North Carolina, and black-footed ferrets in Colorado have all been saved from extinction through captive propagation. In the rural expanse of cropland and turf grass that covers the intersection between Ohio, Michigan, and Indiana, an endangered subspecies of watersnake will soon receive this same treatment—that is, if any still exist. Despite intensive surveys to relocate them, a live copper-bellied watersnake has not been seen since 2019. Now, in a bid to save the copperbelly, the US Fish and Wildlife Service is partnering with the Toledo Zoo to find and capture any remaining individuals to foster the next generation. But can a last ditch captive breeding program save the midwest’s rarest snake?
The copper-bellied watersnake (Nerodia erythrogaster neglecta) is a unique subspecies found in remnant wetlands at the intersection of Ohio, Indiana, and Michigan. This population (located north of 40 degrees north latitude) is categorized as threatened under the US endangered species act. The copperbelly is named for its striking orange or red-orange belly scales which sharply contrast with a black, patternless body. It is a large snake, growing to four and a half feet in length. Neither venomous nor a constrictor, the copperbelly simply overpowers its amphibian prey and swallows it alive and struggling.
The copperbelly inhabits glacial lakes, also called kettle ponds, formed during the last ice age. These shallow wetlands are prime habitat for amphibians like frogs, the copperbelly’s main food. Copperbellies are highly mobile snakes. During the active season, they will traverse hundreds of meters of woodland as they move between ephemeral and permanent wetlands to forage.
In the last 200 years, the copperbelly’s home has been reduced to tiny islands of disjointed ponds and forest surrounded by a matrix of agriculture.
Death By a Thousand Cuts
Copper-bellied water snakes have experienced a 70% decline in abundance from 2001 – 2006. Best estimates suggest there are fewer than 100 individual copperbellies (possibly as few as 40) remaining between Ohio, Michigan, and Indiana. The cause of this decline is mysterious. Habitat loss and fragmentation, agriculture, persecution, road mortality, disease, and inbreeding may all have played a role.
Declines are only accelerating. It is likely there are now too few snakes to support a stable population. Despite their imperiled status, very little conservation work has been aimed at the copperbelly. Until now.
Zoo to the Rescue
The US Fish and Wildlife Service is partnering with the Toledo Zoo to develop a captive propagation plan for the copperbelly. They will collect the remaining wild snakes and use them to start a reproductive colony. Snakes born in this program will be head started—allowed to grow for a few years in the safety of captivity before being released where their parents were collected.
This is an ambitious plan. It has been at least three years since anyone has seen a copper-bellied watersnake in the wild. Even if snakes can be found, no one has ever tried to breed copperbellies before.