It looks like a turtle and swims like a turtle, but this Kiwi-built green machine is more robot than reptile.

To unlock the secrets of green sea turtle power - or how this ocean-going endangered species can swim more than a marathon in a day, while eating just algae and seagrass - a team of Auckland University of Technology scientists have created their own version of one.

It’s already revealed much about its impressive athletic abilities, with a just-published study shedding fresh light on the clever mechanics of its gliding and flapping.

Ultimately, it’s hoped that Cornelia - named in honour of PhD researcher Nick van der Geest’s late grandmother - might inspire a new generation of turtle-inspired underwater robots to aid the conservation and monitoring of our oceans.

Cornelia the robo turtle, pictured in a testing tank. Photo / AUT

Found throughout the tropics and subtropics, green sea turtles are known to swim vast distances between feeding grounds and hatching beaches.

Just how they manage to travel up to 50km a day, despite consuming a low-energy diet of seagrass and microalgae, is down to their special swimming technique.

But there’s been much for scientists to learn about it - and creating their own robot version offered a way for the AUT team to avoid the ethical issues of working with actual animals.

“Even if we were to experiment on a captive turtle, it may not swim with its regular routine in an aquarium setting,” said the study’s lead researcher, AUT biodesign engineer Dr Lorenzo Garci.

Experiments carried out in a special testing tank found the species might only need to propel itself for about a third of the time, meaning it could use an “energy-saving glide” for the rest of the time, all while creating very little drag.

AUT researcher Nick van der Geest with the new robo-turtle he helped create, to discover more about how green sea turtles cover large distances of ocean. It was named Cornelia, after his late grandmother. Photo / AUT

In their study, supported with a $200,000 grant from the Government’s Science for Technological Innovation fund, the authors said they “believe we have created what is the best understanding of the sea turtle’s propulsive routine during its regular swimming pattern”.

“Additionally, we have accomplished this without any animal testing by designing what we believe is the world’s first and only robotic sea turtle that was solely developed to help understand the sea turtle’s propulsion methods,” they said.

“We hope this work will help inspire others to develop robots as a substitute for their biological counterpart.”