By . Ellie Zolfagharifard . The bizarre way a lizard breathes could make it more likely to survive natural disasters capable of wiping out other species. This is according to a U.S. study that revealed the savannah monitor lizard breathes like a bird through a one-way loop. The finding is surprising because the unidirectional airflow of birds was thought to have evolved due to the high-oxygen demands of flight. The bizarre way a lizard breathes could make it more likely to survive natural disasters capable of wiping out other species. This is according to a recent U.S. study that revealed the savannah monitor lizard breathes like a bird through a one-way loop . Researchers at the University of Utah suggest the trait in lizards may have been an adaptation to lower oxygen levels on ancient Earth. For instance, during the early Triassic era 250 million years ago, oxygen made up 12 per cent of air compared with 21 per cent today. ‘It might explain something about why monitor lizards are so successful,’ Mathew Wedel, a biologist at Western University of Health Sciences told Ewen Callaway at Nature. ‘Who knows when the next asteroid hits, maybe monitor lizards will inherit the Earth.’ The upper image is a colourised CT scan showing different airways in the lung of a monitor lizard. The bottom image shows how air flows in a mostly one-way loop through the lizard's lung, as measured by sensors implanted as part of a University of Utah study . The find suggests one-way breathing may have originated 270 million years ago - 20 million years earlier than first thought. Other than the American alligator, the savannah monitor lizard is the only other known reptile found with the ability to breathe in this way. This is in contrast to humans and other mammals who have a two-way, or ‘tidal’, breathing pattern. Tidal breathing means air enters the lungs through airways and then flows back out again the same way. Rather than being partially filled with stale air, like human lungs, a bird’s lungs contain air with much higher oxygen content to help them fly. 'Who knows when the next asteroid hits, maybe monitor lizards will inherit the Earth,' said Mathew Wedel, a biologist at Western University of Health Sciences . The . study showed that air enters the lizard's trachea or windpipe, and then . flows into the two primary airways, which enter the lung. But . then, instead of flowing tidally back out the same way, the air loops back in a tail-to-head direction moving from one lateral airway . to the next through small perforations between them. Other than the American alligator, the . savannah monitor lizard is the only other known reptile found the . ability to breathe in this way - also known as unidirectional breathing. This is in contrast to humans and other mammals who have a two-way, or ‘tidal’, breathing pattern. Tidal breathing means air enters the lungs through airways and then flows back out again the same way. Rather . than being partially filled with stale air like human lungs, a bird’s . lungs contain air with much higher oxygen content to help them fly. ‘It has been thought to be important for enabling birds to support strenuous activity, such as flight. We now know it's not unique to birds,’ said Colleen Farmer, the study's senior author and an associate professor of biology at the University of Utah. But Professor Farmer cautioned that, because lizard lungs have a different structure than bird and alligator lungs, it is also possible that one-way airflow evolved independently. The evolution would have occurred about 250 million years ago in the archosaurs, the group that gave rise to alligators, dinosaurs and birds. The researchers performed CT scans and made 3D images of lizard lungs to visualise the anatomy of the lungs. They surgically implanted flow meters in the bronchi of five monitor lizards to measure airflow direction. Using lungs removed from 10 dead lizards, the researchers measured air flow as they pumped air into and out of the lungs. They also pumped water filled with sunflower pollen or plastic microspheres through lizard lungs, and the movement of the pollen and spheres also showed the unidirectional airflow. The study showed that air enters the lizard's trachea or windpipe, and then flows into the two primary airways, which enter the lung. But then, instead of flowing tidally back out the same way, the air loops back in a tail-to-head direction moving from one lateral airway to the next through small perforations between them. ‘It shows our previous notions about the function of these one-way patterns of airflow are inadequate. They are found in animals besides those with fast metabolisms,’ said Professor Farmer.
The savannah monitor lizard breathes like a bird through a one-way loop .
One-way breathing in birds evolved due to high-oxygen demands of flight .
But in lizards it could have been adaptation to low oxygen on ancient Earth .
The find suggests one-way breathing originated 270 million years ago - 20 million years earlier than first thought .
By . Ellie Zolfagharifard . The bizarre way a lizard breathes could make it more likely to survive natural disasters capable of wiping out other species. This is according to a U.S. study that revealed the savannah monitor lizard breathes like a bird through a one-way loop. The finding is surprising because the unidirectional airflow of birds was thought to have evolved due to the high-oxygen demands of flight. The bizarre way a lizard breathes could make it more likely to survive natural disasters capable of wiping out other species. This is according to a recent U.S. study that revealed the savannah monitor lizard breathes like a bird through a one-way loop . Researchers at the University of Utah suggest the trait in lizards may have been an adaptation to lower oxygen levels on ancient Earth. For instance, during the early Triassic era 250 million years ago, oxygen made up 12 per cent of air compared with 21 per cent today. ‘It might explain something about why monitor lizards are so successful,’ Mathew Wedel, a biologist at Western University of Health Sciences told Ewen Callaway at Nature. ‘Who knows when the next asteroid hits, maybe monitor lizards will inherit the Earth.’ The upper image is a colourised CT scan showing different airways in the lung of a monitor lizard. The bottom image shows how air flows in a mostly one-way loop through the lizard's lung, as measured by sensors implanted as part of a University of Utah study . The find suggests one-way breathing may have originated 270 million years ago - 20 million years earlier than first thought. Other than the American alligator, the savannah monitor lizard is the only other known reptile found with the ability to breathe in this way. This is in contrast to humans and other mammals who have a two-way, or ‘tidal’, breathing pattern. Tidal breathing means air enters the lungs through airways and then flows back out again the same way. Rather than being partially filled with stale air, like human lungs, a bird’s lungs contain air with much higher oxygen content to help them fly. 'Who knows when the next asteroid hits, maybe monitor lizards will inherit the Earth,' said Mathew Wedel, a biologist at Western University of Health Sciences . The . study showed that air enters the lizard's trachea or windpipe, and then . flows into the two primary airways, which enter the lung. But . then, instead of flowing tidally back out the same way, the air loops back in a tail-to-head direction moving from one lateral airway . to the next through small perforations between them. Other than the American alligator, the . savannah monitor lizard is the only other known reptile found the . ability to breathe in this way - also known as unidirectional breathing. This is in contrast to humans and other mammals who have a two-way, or ‘tidal’, breathing pattern. Tidal breathing means air enters the lungs through airways and then flows back out again the same way. Rather . than being partially filled with stale air like human lungs, a bird’s . lungs contain air with much higher oxygen content to help them fly. ‘It has been thought to be important for enabling birds to support strenuous activity, such as flight. We now know it's not unique to birds,’ said Colleen Farmer, the study's senior author and an associate professor of biology at the University of Utah. But Professor Farmer cautioned that, because lizard lungs have a different structure than bird and alligator lungs, it is also possible that one-way airflow evolved independently. The evolution would have occurred about 250 million years ago in the archosaurs, the group that gave rise to alligators, dinosaurs and birds. The researchers performed CT scans and made 3D images of lizard lungs to visualise the anatomy of the lungs. They surgically implanted flow meters in the bronchi of five monitor lizards to measure airflow direction. Using lungs removed from 10 dead lizards, the researchers measured air flow as they pumped air into and out of the lungs. They also pumped water filled with sunflower pollen or plastic microspheres through lizard lungs, and the movement of the pollen and spheres also showed the unidirectional airflow. The study showed that air enters the lizard's trachea or windpipe, and then flows into the two primary airways, which enter the lung. But then, instead of flowing tidally back out the same way, the air loops back in a tail-to-head direction moving from one lateral airway to the next through small perforations between them. ‘It shows our previous notions about the function of these one-way patterns of airflow are inadequate. They are found in animals besides those with fast metabolisms,’ said Professor Farmer.
that revealed the savannah monitor lizard breathes like a bird through a one-way loop. The to the high-oxygen demands of flight. The bizarre lizard breathes like a bird through a one-way suggest the trait in lizards may have been an adaptation to lower oxygen levels on ancient suggests one-way breathing may have originated 270 million years ago - 20 million years earlier than first thought. Other than the American