Duncan Lou Who
The two-legged dog has survived several brushes with death, ever since he was adopted as a three-month-old duncanlouwho/Instagram

Two-legged miracle dog Duncan Lou Who has beaten the odds again and survived an accident while on vacation with his adoptive family at Yellowstone National Park.

The four-year-old boxer was born with his rear legs fused together and a severely deformed pelvis. Named after the fictional character Cindy Lou Who from Dr Seuss's How The Grinch Stole Christmas, Duncan had to have his fused legs amputated.

His owners Amanda Giese and Gary Walters along with their two children, Beast, 15, Jade, 13, and two other dogs, Bullfrog and Garnet, had just started their vacation in Yellowstone on the evening of 4 August, when their vehicle hit a buffalo. The family truck then hit two power poles and rolled several times, when Beast, who was driving, veered to avoid oncoming traffic,

Everyone escaped with minor injuries, including Bullfrog and Garnet, but Duncan was not to be seen anywhere.

"I was afraid that he was lying in the brush somewhere with broken bones or maybe dead," Gary, 46, told People website. "Once power crews put the poles back up and told us it was safe, we turned on flashlights and started looking."

Gary and Beast searched through the night, joined by EMTs, police officers and witnesses who had stopped on the highway to help. Another 30 people showed up to search by the next morning, but no trace of Duncan could be found.

Then a man driving near a rock quarry three miles from the accident site, saw a two-legged dog wandering around. He contacted the family when he heard people talking about the search for Duncan, Gary said.

"He got in touch with me and everyone then refocused their search near the quarry. We were thrilled and amazed that Duncan had traveled so far on his own and had managed to survive the night in bear and wolf country," Amanda told People.

Duncan Lou Who - the miracle dog

The two-legged Instagram and YouTube sensation has survived several brushes with death ever since he was adopted as a three-month-old.

Duncan's first trip to the beach was a YouTube hit with more than 7 million views.

"He survived having his fused legs amputated, he has autoimmune issues and his heart has stopped twice," says Amanda. "Both times I was able to do CPR and bring him back. Duncan has always lived life on level 10 — he's one tough, incredible dog."

"We're all together, and we're all alive," Gary told People website. "This is not only a story of Duncan's survival — it's a story of humanity. We can't thank people enough who dropped what they were doing to come out and help look for our dog."