Before a scorching end to January, it has been a cooler-than-average summer across South-East Queensland, and it appears humans are not the only ones who have been enjoying the drop in temperature.
On the banks of the Mary River at Tiaro, three hours north of Brisbane, endangered Mary River turtles are laying their nests later than usual this season, and their eggs are incubating longer than ever before.
Tiaro Landcare team leader Marilyn Connell suspects the cool weather could be responsible for the change in birthing behaviour for the elusive turtle, best known for breathing from its bum.
After more than 20 years of working with the turtles, Ms Connell said they never failed to surprise her.
"We'd only had 19 [nests for the season] over October, November and December, then in one day, 'bang!' we've doubled our numbers," Ms Connell said.
"Normally they finish laying at the end of December. We might get one or two in early January, but this year, on January 6, we found all these turtle tracks.
"We went looking and low and behold, we had 19 clutches! We never have that many in January."
Typically, after 55 days of incubating, the hatchlings would emerge from their eggs and scurry towards the Mary River.
But Ms Connell said once again, the turtles this season surprised her.
"This year, we had a number of clutches [laid in October and November] that were in late 70s [days of incubation] and one was even up to 85 days.
"Now 85 days is a lot different to 55 days. It's huge … something's going on," she said.
Cooler conditions
The Bureau of Meteorology said that across the Wide Bay region temperatures were below-average throughout December and the beginning of January.
"It was due to a combination of a ridge along the east coast, and just persistent south-easterly winds coming onshore. So, it was giving the temps a fresher feel as well," meteorologist Felim Hanniffy said.
"Maximum temperatures, if you take the average of them, were generally on the cooler side.
"Anywhere from 2 degrees Celsius to 3C [lower], particularly inland."
Research funded by Tiaro Landcare and carried out by the University of Queensland School of Biology and Sciences found that Mary River hatchlings thrived under cooler incubation temperatures.
"The embryos that were incubated at a much higher temperature were smaller," Ms Connell said.
"When they were released into the water, they didn't dive as deeply as others and they came to the surface a lot more frequently.
"Of course, if you're not diving down to the bottom and hiding there's more chance that somebody who wants to eat you is going to find you."
Investigations to continue
Ms Connell said the team would continue to investigate the influence of temperature on the nesting and hatching of Mary River turtles.
"For another species of turtles that's found in Australia, once the temperatures are below 22C, the embryos really slow down their development," she said.
"So, we're suspicious that that's probably what's happened this year. We don't know for sure.
"But nature is what it is … it's unpredictable."
Local conservation volunteer Wayne Kassulke, who has spent the past 12 years visiting the Mary River said he enjoyed learning new things about the bum-breathing species that defined the small town of Tiaro.
"We come across different things all the time and we're always learning from the different things we pick up," he said.
"It's always an adventure, and I don't mind running around the countryside for them."
