You shouldn’t name a crocodile or ascribe it human emotions. It’s not a pet. It’s a wild and primitive creature with a lot of very sharp teeth and a crazy powerful jaw.

But that didn’t stop anyone from naming the sole crocodile living at Dry Tortugas National Park.

Cletus. That's what most people on the park staff call the croc. A few call him Carlos. No one remembers why.

The Dry Tortugas are a small, remote cluster of islands 70 miles west of Key West. Cletus is the first American crocodile spotted there since Ponce de Leon arrived in 1513. He hasn’t seen another member of his own species since he swam out here in 2003, which makes it difficult not to think of him as the world’s loneliest crocodile.

Mark Parry, a wildlife biologist with the National Park Service, specializes in monitoring large reptiles, such as alligators and crocodiles. He catches Cletus every few years with a crew of biologists and park staff.

“This is not going to happen guys. But if I say ‘it’s coming in the boat,’ get on the other side of the console," he said. "Let the animal do its thing.”

The park staff catches Cletus to do a growth health assessment on the crocodile, said Tracy Ziegler, who oversees science projects at the park.

“We haven’t captured him in quite a few years," she said. "We’re trying to see whether or not he grows faster or slower in this environment.”

This environment refers to a place without any fresh water. Crocodiles usually live in a mix of salt water and freshwater. The biologists have some baseline data from when they caught Cletus once before, six years ago.

American crocodiles differ from the more common and more aggressive American alligator. There are only an estimated 2,000 to 3,000 American crocodiles in the U.S., all in extreme South Florida. The species received federal protection in the 1970s, when its population had fallen to about 300 animals, largely due to development and hunting.

Mark Hedden

FINDING CLETUS

It was windy when the boat set out, and there was a full moon. Parry and crew scanned the shoreline with a spotlight. Crocodiles have highly reflective retinas, which makes it hard for them to hide in the the dark.

For a long time there was nothing. But then they saw it - the animal’s eyeshine. It looked like two golden marbles, disembodied, glowing under a bush.

“He’s on the very low side of where that bush kind of tapers down. He’s right there,” said Parry, guiding the boat's captain.

When it was too shallow for the boat to go farther, Parry slipped off the bow into knee-deep water. He approached the bush where the crocodile was, poked his head in, then stuck the snare pole in and slipped a lasso over the animal’s head.

He walked the animal along the shore like an angry dog. The croc’s mouth was open. Its teeth gleamed in the moonlight.

Three people from the boat met Parry on the beach, where the croc was in shallows. The croc thrashed.

“Give him some room. Don’t let him get that close to you,” Parry said to the crew.

He assessed the situation, “All right, there’s nothing for him get snagged on. Let him feel like he’s all right. He’s not gonna drown. He hasn’t fought that much.”

Parry approached the croc from behind. He quickly straddled the croc’s shoulders and sat on him. He pressed down on the snout until it closed, then kept it shut with one hand as he wrapped several loops of electrical tape around it.

An American Crocodile can crush a pigs skull with it’s jaws, but once its mouth is closed, it doesn’t have a lot of strength to open it.

The crew then carried the crocodile up onto the beach.

“So what we’re going to want to do is get him as straight as humanly possible. Well, not humanly possible,” Parry said.

Parry put a knee on the crocs neck, pulled out a yellow tape, and started measuring like a tailor.

“We need head length, snout vent length dorsally, total length, tail girth, mass, sex...” he said.

Getting all the measurements took about half an hour. Cletus’s yellow eyes stared straight ahead the whole time.

The croc was just under 9 feet, and 155 pounds – about a foot longer than the last time they caught him six years ago. Parry said he seems to be growing at a pretty normal rate. He could get up to 12 feet.

“All right, we’re going to take him into the water tail first,” Parry said.

The crew carried the croc back out into the shallow water. His legs hung loose, like a sleeping child’s. They put him down and stepped away. Parry yanked on a rope and the tape came off the croc's snout.

Cletus immediately spun around, dove beneath the surface, and merged with all the other shadows of the night.