Nearly one fifth of all reptiles — turtles, snakes, lizards and crocodiles — are on a slippery slope toward extinction due to loss of habitat, overharvesting and other factors, a new report says.

The study is the first of its kind to summarize the global conservation status of reptiles. More than 1,500 species were selected at random from around the world for conservation assessments in an effort to gain a representative sample.

The results highlight "conservation priorities and knowledge gaps which need to be addressed urgently to ensure the continued survival of the world’s reptiles," more than 200 researchers led by Monika Böhm at the Zoological Society of London write today in the journal Biological Conservation.

"Nearly one in five reptilian species are threatened with extinction, with another one in five species classed as Data Deficient."