Some 19 percent of the world's reptiles are in danger of extinction, according to a joint study published by the Zoological Society of London and experts of the International Union for Conservation of Nature, or IUCN.

The study, published in Conservation Biology magazine, is the first to compile the state of conservation of 1,500 reptile species worldwide.

Of the threatened species, 12 percent are considered "critically endangered," 41 percent are said to be "endangered" and 47 percent are "vulnerable" to going extinct.

The study is an important step toward evaluating the global conservation status of reptiles, said Philip Bowles, coordinator of the IUCN Species Survival Commission and a specialist in snakes and lizards, adding that "the findings sound alarm bells about the state of these species and the growing threats they face."

"Tackling the identified threats, which include habitat loss and over-harvesting, are key conservation priorities in order to reverse the declines in these reptiles," Bowles said.

The worst threats to reptiles include man-made habitat loss from agriculture and logging, and being harvested by people, the study said.

In total numbers, the experts estimate that 30 percent of all fresh-water reptiles are close to extinction, a percentage that rises to 50 percent in the case of turtles, which are a "sales asset" on the domestic and international markets.

Though land reptiles are in somewhat less danger, they are very much a prey to human pressures, since they cling to very specific biological and environmental habitats and have little mobility.

Reptiles appeared on Earth 300 million years ago and have had a long, complex history, according to the researchers who seek to protect the world's snakes, lizards, turtles and crocodiles. EFE