Lizard research discovers native reptiles evolved to detect introduced predators

[Flaviemys purvisi]

3 Nov 2018
ABC North and West
By Shannon Corvo and Gary-Jon Lysaght


Professor Dale Nimmo says native skinks and geckos can detect danger, but not individual predators.
ABC Rural: Daniel Fitzgerald


Scientists at Charles Sturt University have discovered that native reptiles are smarter than previously thought.

The research published in the Royal Society Open Science journal revealed native lizards can identify foxes and wild cats as predators, even though they have not evolved alongside them.

Ecologist Dale Nimmo said the findings proved that native reptiles could survive the onslaught of destructive predators.

Skinks will sometimes forego food to protect themselves from danger.
Supplied: Ben Parkurst


"We exposed a native skink and a gecko to the scents of the cats and the foxes and a bunch of native species including the spot-tailed quoll and the brown snake," Professor Nimmo said.

"What we found was that these native reptiles were able to associate the scent of the cat and the fox with a risk.

"They avoided spaces where their scents had been applied in the same way that they would if it was a scent of a dingo or a quoll or a brown snake."

How are they so smart?
Professor Nimmo said there are three reasons why native reptiles are intelligent enough to know foxes and cats are predators.

Geckos and skinks have evolved to detect predators in less than 150 years.
Supplied


"The first is that there's this idea that when a native animal evolves with a suite of native predators, they need to adapt a flexible approach to detecting predators," he said.

"The second possibility is that it's been 150 years since foxes and cats were introduced to the region and that's enough time for quite a number of generations."

Although some species take hundreds of years to evolve, Professor Nimmo said the skink could have evolved in far less time than that.

"The third possibility is that these animals are actually learning within the time frame of their life that the scent of a fox is an indicator of a fox being around," he said.

Although Professor Nimmo said skinks and geckos are able to detect when predators are nearby, they sometimes evade danger at the risk of not getting a meal.

"What these animals are doing is going up to a potential food source, having a look at it, checking out the environment, sensing a predator and then not eating the food," he said.

"Food is, obviously, one of the major resources animals need to survive and produce offspring."

What next?
Professor Nimmo said future research will aim to determine how native reptiles have been able to adapt.

Skinks recognise foxes and cats, as well as dingoes and quolls, as predators.
ABC Open: Lucy Bradshaw


"There are the three possibilities but it's very hard to differentiate between them, but that's what we might be trying to do in future studies," he said.

"We don't know if they learn how to avoid predators or if it is a behaviour inherited through their genes.

"[But] we do know that they recognise the scents of foxes and feral cats as a threat and respond.

"This gives some hope for some native species as we seek to predict or prevent the impacts of invasive predators on Australian wildlife."

 

[Sdaji]

That's some pretty flawed research! :O

 

[nick_75]

The behaviour of avoiding predators is instinctual thus inherited through genes. Examples can be found throughout the animal kingdom in all phyla. When you are small, the best behaviour to survive is to hide.

It is certainly a strange topic of research seeing that the avoidance of predation (at the cost of other life essentials) is already well documented. Especially in small species that are low in the food chain. I'm not sure if the species used in the research are detecting the introduced predators specifically as a threat, thus evolving over a very short period of time to recognise new predators or whether it is the natural/instinctive behaviour to hide.

It would be very hard to prove that predator recognition evolution is occurring as the hide to survive behaviour is so intrinsic to survival.

 

[dragonlover1]

The behaviour of avoiding predators is instinctual thus inherited through genes. Examples can be found throughout the animal kingdom in all phyla. When you are small, the best behaviour to survive is to hide.

It is certainly a strange topic of research seeing that the avoidance of predation (at the cost of other life essentials) is already well documented. Especially in small species that are low in the food chain. I'm not sure if the species used in the research are detecting the introduced predators specifically as a threat, thus evolving over a very short period of time to recognise new predators or whether it is the natural/instinctive behaviour to hide.

It would be very hard to prove that predator recognition evolution is occurring as the hide to survive behaviour is so intrinsic to survival.

My first thought was that they could smell the meat eaters scat and took warning from that, not necessarily that they reacted to NEW predators.

 

[Sdaji]

My first thought (shortly before many others!) is that they are claiming the skinks and geckoes have learned to recognise foxes and predators since their arrival in Australia. This assumes (probably incorrectly) that they would not have recognised them as predators 500 years ago. To be a valid study you would first need to demonstrate that geckoes and skinks 500 years ago did not recognise cats and foxes as predators. As a biologist with a major in zoology and an honours year in ecology I'd gladly bet money on that being wrong. Show an axolotl to a Death Adder and it will gladly eat it immediately, despite evolving on opposite sides of the planet and encountering each other for the first time. Same with Americans feeding anoles to their Carpet Pythons and Chondros (naturally occurring on opposite sides of the planet), etc.

This is an embarrassingly flawed study!

 

[nick_75]

My first thought was that they could smell the meat eaters scat and took warning from that, not necessarily that they reacted to NEW predators.

Essentially yes, organisms that are predated upon will react to any evidence of a predator. Whatever the evidence is, scat, scent trails etc. the response will be to hide.
[doublepost=1547028345,1547027685][/doublepost]

My first thought (shortly before many others!) is that they are claiming the skinks and geckoes have learned to recognise foxes and predators since their arrival in Australia. This assumes (probably incorrectly) that they would not have recognised them as predators 500 years ago. To be a valid study you would first need to demonstrate that geckoes and skinks 500 years ago did not recognise cats and foxes as predators. As a biologist with a major in zoology and an honours year in ecology I'd gladly bet money on that being wrong. Show an axolotl to a Death Adder and it will gladly eat it immediately, despite evolving on opposite sides of the planet and encountering each other for the first time. Same with Americans feeding anoles to their Carpet Pythons and Chondros (naturally occurring on opposite sides of the planet), etc.

This is an embarrassingly flawed study!

Yes, it is certainly impossible to prove that the introduced species have been specifically recognised as predators, rather than recognised as something larger that the lizard/gecko and thus to be avoided. The fact that the lizards and geckos are responding to the scents does not prove that the introduced species have been recognised. You could introduce the scent of any predator to the study species and observe a reaction.