A photo posted by a snake biologist is confounding Twitter users, who have struggled to find a venomous snake hidden among a bed of leaves in the image.
"Received this from a fellow HERper this morning," tweeted Helen Plylar, reports Mashable. "No caption needed, the task was implied: 'can you spot the snake?'"
The photo, on first glance, appeared to simply show brown leaves on the ground, but on closer inspection, users began to spot the elusive reptile.
According to Plylar, the photo, which shows a copperhead snake, was taken by Jerry Davis from Texas.
"If y'all haven't found it yet... Copperhead, aka Agkistrodon Contortix," Plylar tweeted, along with a guide to the snake's location in the picture, below. "Cute but venomous, so no touchy!"
Plylar reportedly received at least one photo of a dead snake after posting the snake-search photo, and warned others not to harm snakes, WGHP reports.
"For everyone enjoying this puzzle, please remember: snakes deserve to live just as we do," she tweeted. "Treat them with care and respect, not hate and fear."
Copperhead snakes are common in North America, reports Live Science. While they are apt to bite, the copperhead's venom is relatively weak, and their bites are rarely fatal to humans.
The snake's name comes from its head, which is a red copper hue. Similar to rattlesnakes and water moccasins, copperheads are pit vipers, which have heat-sensing pits between their eyes and nostrils. These pits enable the snakes to detect small changes in temperature, allowing them to find their prey more easily.
Herpetologist Jeff Beane said the copperhead's "behavior is very much like that of most pit vipers."
"Temperament varies among individuals," explained Beane. "Some are very reluctant to bite and others are very quick to bite defensively."
The snakes, which are active at night, are more likely to get defensive if encountered during those hours than during the daytime, when they rest. If a copperhead is agitated, the creature will vibrate its tail quickly while emitting a "musk" with a strong scent.
According to the USDA Forest Service's facts on snake safety, most snake bites occur between April and October. The agency recommends carrying a flashlight when outdoors at night, and wearing hiking boots that go above the ankle to avoid snake bites.
The Forest Service also suggests avoiding tall grass or heavy underbrush where snakes may hide during the daytime, and not to turn over rocks or logs, because snakes may hide beneath them. The agency also warns to stay away from any snake that you cannot identify with certainty as being a safe species.