MIAMI — Talk about a survival instinct.

An injured horse found on a Florida highway last week narrowly escaped a death sentence. He somehow made his way out of a trailer that was taking him to his own execution.

He ended up saving his own life.

Authorities say the horse was being transported to be “euthanized, but had different plans,” the sheriff’s office posted on Facebook.

Now, the driver of the trailer is in trouble with the law for abandoning the animal that police nicknamed Highway. After his harrowing adventure, the horse was found last Friday on Interstate 75, north of Micanopy.

It was all a mystery at first. Why was a horse roaming the highway?

The Alachua County Sheriff’s Office says the mystery was solved after people on social media responded to the animal’s plight. Then tips poured in.

Turns out, the 12-year-old gelding’s owner had no use for the animal anymore, said sheriff’s spokesman Art Forgey. Then, the person tasked with transporting the doomed animal either didn’t secure the trailer gate properly or the animal kicked his way out, Forgey said.

A passing truck driver on the highway spotted the open gate on the horse trailer and flashed his lights at the truck driver. The driver pulled over at the signal, closed the gate and then “nonchalantly” drove away, Forgey said.

The sheriff’s office considers the driver a suspect and is preparing a warrant for his arrest on animal abandonment charges, Forgey told the Miami Herald. The driver was not identified.

The case of Highway the Horse started getting attention after it was picked up by an equine advocates site called Stolen Horse International.

Highway, previously named Jet and Spartan by other owners, is on the mend but not out of danger. He is being treated for road rash, and a large open joint wound.

“His story has certainly turned out to be one for the books,” say the caretakers at Springhill Equine Veterinary Clinic in Ocala where Highway underwent surgery. “He is not out of the woods yet, but we are more optimistic with each day that he is on the right road to recovery.”

The deputies who responded to calls about the wandering horse found him “docile,” standing in the grass on the side of the road.

Forgey said the outpouring of support has been “overwhelming” and that the sheriff’s office has received calls asking about the horse’s welfare from as far as away as Australia.

“He will be well taken care of and hopefully make guest appearances on our Facebook page from time to time just to say ‘hey’ or ‘hay,’ the office wrote on Facebook.

“Cats have nine lives,” Forgey said. “We’re hoping this horse gets his.”