“It’s a dinosaur backbone!” One February morning, around 30 researchers and workers hammered away at an excavation site in the middle of sugar cane fields stretching beyond the horizon in Suranaree, about 260 km northeast of Bangkok.

Large rocks were first cut into pieces around 30 cm sq. and then broken into smaller pieces to comb through for fossils of dinosaur bones and teeth, as well as fish scales.

The project, in the central province of Nakhon Ratchasima, is a joint effort between the Fukui Prefectural Dinosaur Museum and Thailand’s Khorat Fossil Museum. The excavation work has unearthed about 30,000 fossil pieces, including from newly discovered species, over the past six years.

The Fukui museum initiated the excavation in 2007 with the aim of tracing the roots of dinosaurs that existed in Japan.

“Like in Katsuyama (where the museum is located), the same geological stratum from the early Cretaceous period exists beneath the site in Thailand,” said Yoichi Azuma, special curator at the museum. “They also share in common the kinds of dinosaur fossils found.

“If we can draw comparisons based on research results over a 25-year span, it would provide clues to tracing these roots,” he said.

At the Suranaree site, bedrock from the early Cretaceous period — around 120 million years ago — lies only about 1 meter below ground level. Local legend has it that the soil is reddish because it is mixed with dinosaur blood.

But breaking the rocks into small pieces with a hammer is much easier said than done. The excavation work is conducted during Thailand’s dry season, around January and February. Although this is considered the coolest part of the year, temperatures in the afternoon still rise above 30 degrees.

Covered in sweat and dust, the workers pound the rocks with hammers, but take great care not to chip off any whitish fragments — bits of bone fossils.

After finally managing to carefully remove a 2-cm white chunk from a rock and thinking it might be a dinosaur tooth, one worker took it to a researcher only to be told: “That’s a piece of fossilized dung. Not needed.” Even for the local excavators, it takes years of experience to be able to tell the difference.

During that day’s excavation, the researchers and workers unearthed fossil pieces of not only dinosaurs but also turtles and freshwater sharks.

Although very little is known about the early Cretaceous topography of the area, judging from the findings “it seems that the remains of living creatures flowed slowly along the river and got deposited here,” said Yoshikazu Noda, a 53-year-old researcher at the Fukui museum who is part of the team.

Rattanaphorn Hanta, 33, a researcher with the Khorat Fossil Museum, said: “This year, we have found dinosaur teeth that have not been seen before. If these are confirmed to be newly discovered species, it would further expand the variety of dinosaurs that existed in Asia.”

To deepen cooperation among Asian researchers, especially those from China, South Korea and Thailand, an Asian dinosaur association will be launched in the summer with the Fukui Prefectural Dinosaur Museum serving as its secretariat.

Dinosaur excavations in the city of Katsuyama, Fukui Prefecture, began in earnest in 1989 after a complete crocodile skeleton was unearthed locally. In the first year alone, researchers at the Fukui Prefectural Museum, the predecessor of the dinosaur museum, discovered around 300 dinosaur fossils.

“In just one week of digging, the number (of items excavated) surpassed the total number reported nationwide up until then,” said Azuma, the curator, who was an employee of the museum at the time.

“I was convinced this area would become Japan’s biggest producer of fossils,” he said.

Of the four dinosaur species that have been newly discovered and named in Japan, three were dug up by the museum’s workers and researchers — including the Fukuiraptor, a medium-size carnivore that roamed the archipelago in the early Cretaceous period.

Despite its remote location in a mountainous area of the Chubu region, facing the Sea of Japan, the museum is popular and considered to have one of the world’s major dinosaur exhibits.

In the fiscal year that ended in March 2012, it had more than 500,000 visitors, around six times the average number of guests for natural history museums nationwide. The total visitor count since the museum’s opening in July 2000 had exceeded 5 million as of late March.

As the museum is directly and actively involved in excavation projects — locally in Katsuyama and overseas at the Suranaree site, as well as in China’s Zhejiang Province — its collection of exhibits continues to grow.

One of the reasons behind its popularity is that visitors can take part in special events to gain hands-on excavation experience, with many of the programs open to parents and children. Families with kids comprise about 80 percent of the total number of visitors, according to museum officials.

Walking through its exhibits, visitors can see up close around 40 complete skeletons of a variety of dinosaurs, as they are not kept behind glass cases, giving guests the strong sensation that they are walking through a world of dinosaurs.

“That’s why many visitors come just by word of mouth,” said Masayoshi Shirasaki, a Fukui prefectural official who was in charge of the museum when it was first established.