Two New Jersey herpetologists exploring an area known for its timber rattlesnakes stumbled across a rare find: a newborn two-headed rattlesnake slithering across the ground.

"I was totally blown away. You hear about things like that ... but it's extremely rare," Herpetological Associates' regional manager Dave Schneider told NBC News on Friday. "It was pretty crazy."

Schneider and his colleague, Dave Burkett, found the snake about two weeks ago in the Pine Barrens, a heavily forested area in the southern part of the state, after they were told that a female timber rattlesnake had recently given birth.

As Schneider was snapping photos of some of the baby serpents, Burkett spotted the two-headed creature.

The venomous snake — named "Double Dave" because of its two heads and the two Daves who found it — was taken to the Herpetological Associates in Pemberton where it will be monitored.

Schneider said because the snake has an extra head it might not have survived long in the wild, explaining that it could have trouble getting away from predators.

Because timber rattlesnakes are an endangered species, Herpetological Associates had to get permission from the state to keep it.

Double Dave, who is roughly 10 inches long, has been doing well and appears healthy. Schneider said he has noticed that the "two heads are working independently" and sometimes the serpent will stiffen up because the heads want to go in opposite directions.

"But other than that it's normal," he said. "So far, so good."

Herpetological Associates plan on giving Double Dave an X-ray soon to make sure all of its organs are working properly.

Timber rattlesnakes can live 20 to 30 years, Schneider said. He hopes Double Dave will have a long life span as well.