Scientists have discovered how lizards breathe underwater by using a bubble of air trapped on their nose.
It had previously been thought that the reptiles held their breath for up to 16 minutes when they submerged.
But close scrutiny of new footage of a land-dwelling river anole reveals that it breathes from a bubble of air believed to be held around its head and throat.
Scientists say it is similar to how a diver breathes from an air tank.
Footage, filmed in Coto Brus, Costa Rica, captures the reptile’s nose as it bulges at the bridge – revealing the substantial air pocket.
But the bubble only remains in place for a second before the bulge completely disappears.
This process repeats every few seconds as inhalation and exhalation of the air bubble allows for ‘trading’ of fresh air among these air pockets.
Dr Lindsey Swierk, who captured the footage, said she ‘doesn’t know too much’ about the phenomenon yet but believes it could be similar to a technique used by a diving beetle.
‘Diving beetles will trap air bubbles on their body surfaces using surface tension, and they can breathe the air within these bubbles,’ she told Business Insider.
Dr Swierk had been studying the water reptile for four years before the discovery was made.
The Assistant Research Professor at Binghamton University in New York said: ‘This behaviour opens up fascinating new doors that allow us to investigate how terrestrial animals adapt to aquatic habitats.
‘I started looking into this odd behaviour in 2015, when I noted a lizard spending 16 minutes completely submerged.
‘I was both impressed and confused about the length of the dive, which motivated me to take a closer look with an underwater camera.
‘We are still figuring out what is going on, but it’s certainly an exciting hypothesis to examine.’
Dr Swierk has studied lizards for 10 years and said she has never witnessed this phenomenon before – which she believes is to help the reptiles avoid predators.
She said: ‘We really don’t know too much about this phenomenon yet, which makes it so interesting.
‘I think it’s possible that some air pockets are being trapped around the anole’s head and throat, and the inhalation and exhalation of the air bubble allow for some ‘trading’ of fresh air among these air pockets.
‘Or perhaps it has to do with using the bubble to get rid of CO2.
‘It’s easy to “disappear” to a predator’s eye once you hide underwater for a few minutes.’
However, Swierk is quick to caution that her work is in its infancy, and she is simply reporting on a “cool observation”.
No study has been published on the topic, although a short natural history observation will be published in the March issue of Herpetological Review. Nevertheless, she believes her work could eventually lead to a better understanding of how evolution has led to multiple solutions to the same problem – how species remain underwater for long periods of time.