IF you spend much time around Shenzhen’s lakes and ponds, you may encounter a curious snake with an olive-greenish coloration, white throat, yellow belly and reddish eyes. The plumbeous water snake (Hypsiscopus plumbea) is venomous; however, it is harmless to humans and plays a vital role in Shenzhen’s ecosystem by controlling frog populations and dispersing fish eggs.

The plumbeous water snake averages around 50 centimeters long and possesses a short, stocky body. Its name comes from its olive-brown to lead-grey coloration, which helps it blend into the rocky edges and muddy banks where it likes to sun itself.

Plumbeous water snakes mainly feed on small fish, frogs, tadpoles and fish eggs. They hunt by stealthily swimming just below the water’s surface, searching for prey.

Reproduction in these snakes begins in April when males chase after and wrestle with females. Once a male has successfully mated with a female, she will search for a secluded spot on land to lay her eggs sometime in May or June. The young snakes emerge two months later, fully equipped to hunt small fish and frogs.

Plumbeous water snakes play an essential role in Shenzhen’s ecology. They help control populations of fish, frogs, and small rodents that feed on fish eggs and young fish. Their presence indicates healthy water quality since these snakes cannot tolerate polluted environments.

Plumbeous water snakes spend almost their entire lives within a few feet of shore, basking on branches and rocks during the day and hunting from just below the water’s surface at night. If you’re lucky enough to spot one, take a moment to appreciate its beautiful eyes and iridescent olive scales.