A team of NSW Riverina-based researchers are readying to re-write the ecological history books after stumbling across a rare and endangered species of wetland snake that was thought not to exist in the area.
The nocturnal, frog-eating grey snake has not been seen or recorded in southern NSW for 65 years until Charles Sturt University academic Dr Damian Michael accidentally sighted it two years ago.
"I was working near the Redbank Weir, it was my first time out looking for frogs and I wasn't expecting to see it," Dr Michael said.
"But within two hours, I sighted one."
Canvasing the wetlands and surrounding areas where the rivers meet, Dr Michael has since heard from landholders that there may be a vast den of the rare and small snake in the region.
"So far we've been finding them in reasonably high populations around the wetlands where there is an abundance of frogs," he said.
"In one area during a night spotlight we found about five in an hour, but as soon as you get 50 to 100 metres away from the wetlands they start to disappear again."
Other snakes - including the brown, black and tiger species - take the place of the smaller grey snakes once any distance from the wetland has been achieved.
"Other snakes feast on lizards not frogs, so they can be found further away from the wetlands," Dr Michael said.
"There probably is a lot of interactions between the species during the day, but the tiger snake and the black snake, for example, are more active during daylight hours.
"The grey snakes seem to have their pick of the smorgasbord of frogs during the night."
While the snakes can grow to about 60cm, so far those found by Dr Michael and his team have averaged to about 40cm.
At a glance, the grey snake can be mistaken for other more common varieties, which Dr Michael said, is partially the reason they have gone undetected in the area for more than half a century.
"Superficially they can look like a juvenile brown snake, they will have the same dark head but that is lost on the brown snake when they grow to about two feet," he said.
"You have to inspect the scales and belly to know, and that requires picking it up, which I don't recommend."
Landowners or wetland walkers who sight a grey snake are encouraged to snap a picture and upload it to the iNaturalist app.
"These snakes are most active at night while others are seen in daylight or at dusk, so it's likely that most people won't see a grey snake," Dr Michael said.
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But whether the rare snakes might be found in Wagga, Dr Michael is unconvinced.
"The Wagga wetlands are probably too far upstream for the grey snake. It's probably not going to be found in Albury either," he said.
"They prefer low deltas and are very dependent on the floodplain. When that dries out, they need the wetland again."
Dr Michael and his team are now micro-chipping the snakes when they find them, in order to understand their population sizes and movements around the river systems.
"We want to know where do they go when the wetlands dry up? Some of these areas can be dry for two or three years, some have been dry during the drought for a whole decade," he said.
"We do know that they can give birth to up to 16 babies at a time so that will repopulate them quickly. It's a sort of bust or boom strategy that a lot of wildlife in Australia have."