Rescuers hail the survival instincts of a pet dog that got lost during a massive wildfire and lived through a freezing winter in California's mountains

• Ricardo Rodriguez lost his dog, Russ, when camping in Lake Tahoe in September before the Caldor Fire.
• There was no sign of Russ, no shelter found him, and temperatures plummeted as winter took its grip.

After going missing for four months, a lost pet dog was miraculously found huddled in the freezing snow at Twin Peaks, near Lake Tahoe.

In early September, Ricardo Rodriguez was on a camping trip in the Lake Tahoe area with four friends and his three-year-old pitbull mix Russ. But the idyllic trip was cut short after the Caldor Fire engulfed the area, forcing the group to flee.

In the chaos of the blaze — which ultimately destroyed almost 1000 structures — Russ ran away, forcing Rodriguez to leave without him.

He never heard if Russ was safe.

However, on December 16, a skier saw a dog bundled in the snow. Unable to reach the animal, Wendy Jones, founder and executive director of Tahoe PAWS & TLC 4 Furry Friends, an animal search-and-rescue non-profit group, was alerted.

Volunteers Leona Allen and Elsa Gaule immediately started the mission to save the dog.

As they trekked up the snow-bound hill, they saw the dark mass of the dog. The volunteers assumed he was dead, as the freezing temperature would have made it hard for him to survive.

And then he lifted his head.

The volunteers shouted with joy and then quickly had to bundle the scared dog — luring him with treats — and sled with him down the hill.

Although he was fearful, after four months of surviving snow and fire alone, he rested his head in Gaule's hands, showing he was trusting.

The rescuers wrapped Russ in a warm blanket and sled him down the mountain to the El Dorado County Animal Services Diamond Springs shelter.

He was in surprisingly good health, the director of the animal response team and founder of Tahoe Paws, Wendy Jones, told Insider, describing Russ as "cold, hungry and thirsty, but happy and sweet."

Henry Brzezinski, Chief of El Dorado County Animal Services, told Insider that Russ was roughly 15 lbs underweight, possibly surviving off food from nearby restaurants.

When Russ got the all-clear, the medical staff checked him for an ownership microchip. Rodriguez then received the phone call he'd been waiting for.

"I was ecstatic," he said, "I was looking forward to helping my dog find his way back home," Rodriguez told CNN.

"After months of not hearing back from anyone, I assumed he was in good hands with a different owner," Rodriguez told CNN, "I was hopeful that one day he would return."

On December 26, the pair were reunited, and Russ was safe and warm once more.

There's no tangible explanation for how Russ survived so long in such brutal weather conditions. There is a chance, Brzezinski tells Insider, he was taken in by someone only to escape again.

Jones added that "dogs go into survival mode. They find food, water, and a safe place to hunker down."