National Park

Saguaro Nat’l Park’s citizen-powered Gila Monster Project has been going on for over a decade

Jacob Owens

At the entrance to the sandy Broadway trail in Saguaro National Park, there is a flyer that doesn’t quite fit. The white sheet, which hangs among the signs prohibiting pets and horses from dirt trails, contains an image of an orange and black Gila monster and a simple question: “Have you seen me in the national park of Saguaro?”

Rather than just a warning against the poisonous lizard, the ad invites visitors to take part in a science project that has been going on for many years.

The Gila Monster Project has been inviting members of the public to submit photos of reptiles for over 15 years. Over 1,000 images later, the initiative is still going strong, and photographs from the public have become the heavy lifting.

The photos began as a way to supplement the University of Arizona’s ongoing research in Saguaro National Park and engage the public, said Kevin Bonine, who helped start the science enterprise in 2005. .

“And we could get species information that way and also inspire people, national park staff and visitors and residents who live nearby, inspire them to be more curious about some of the history nature of the region’s ecology,” said Bonine, director of Biosphere 2.

The colorful reptile is a southern Arizona staple also found in northern Mexico and known for its orange and black scale pattern. The beaded lizard can grow up to about 22 inches long and eats things like eggs along with small mammals and birds. The poisonous animal is not aggressive, but it can bite if forced defensively and transfer the venom through its teeth.

Although not endangered, the reptile is listed as “near threatened” by the International Union for Conservation of Nature. Gila monsters are protected in Arizona from death, removal, or harassment.

The university’s research included taking small tissue samples from the creatures to examine their DNA, Bonine said. Shortly after the small-scale research began, officials began encouraging the public to submit photos of the lizards.

The reptiles were chosen due to factors including their elusive nature and the fixed patterns of mature Gila monsters, which return even after shedding their skins, he said. These patterns lent themselves to what Bonine called the “public science” part of research.

Unlike the more complex work of studying lizard genetics, which UA students participated in, members of the public could submit photos to help identify the creatures by their unique scale patterns, which are often compared to fingerprints.

“It’s not like rings and walls, kind of like we have on our fingerprints,” Bonine said. “It’s sort of the spacing and pattern of the black pigmentation versus the type of salmon or pink or coral color that comprises the other part of their pattern.”

Don Swann, a biologist from Saguaro National Park, has been involved in the work on the Gila monster from the beginning and is helping to continue it today. About six or seven years ago, the university’s involvement in the project waned and the park’s role grew along with the public’s, Swann said. This led to flyers being placed on the trails and further encouraging public assistance.

Once received, the images are organized by date and location and analyzed to see if the person in the photo matches someone already in the system. If someone submits multiple photos of the reptile from different angles, the photos are merged together in Photoshop, he said. The image is then scanned by a system that compares it to other nearby shots. This process is currently done manually, with the help of a single volunteer who comes once or twice a week.

Original AU-led research found that the park had a genetically diverse and healthy population of lizards. Further work aims to obtain information such as the lifespan of Gila monsters in the wild, their number of moves and when the lizards are active.

“By taking a long-term view and using these photographs provided to us by visitors, we can begin to get a glimpse of an animal that is still something of a mystery not just to most of us but to most biologists,” Swann said.

Although it will be several years before the results are published, the data indicates that the Gila monsters are very active in April and May and appear at night during the monsoon season, he said. Based on current data, Swann predicts that reptiles are “homebodies” who tend to stay in a relatively small area. Some individuals photographed in the area have proven that lizards can live for at least 12 years outside of captivity.

Officials have also discovered that a small percentage of lizards have part of their tail missing, which does not grow back. The culprit is unknown, Swann said, but one hypothesis is that ground squirrels could be responsible for the damage to the extremities.

“We find evidence that the tails are somehow missing at the end, which we suspect to be some kind of predator,” he said. “We don’t know, we haven’t seen that, but we’ll see the tail is missing at the end or the bone is exposed where it broke.”

About 660 individuals have been identified since 2001, Swann said, and more than 150 additional photos are blurry or partial and cannot be compared to existing images. The majority of sightings have been in Saguaro East compared to the park’s western district, which is drier and at a lower elevation, Bonine said.

The public is encouraged to continue submitting photographs of the lizard, but officials request that images be from within or very close to Saguaro National Park. Photos can be submitted to [email protected]

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