How do reptiles compensate for a lack of supplemental oxygen intake through moist skin like that of amphibians?

2 Responses to “How do reptiles compensate for a lack of supplemental oxygen intake through moist skin like that of amphibians?”

1. Southpaw says:

   July 7, 2010 at 6:12 am

   Reptiles have developed more complex lungs compared to amphibians to compensate for the lack of oxygen intake through mosit skin. In amphibians since most of the gaseous exchange occurs via their moist skin, their lungs are simple balloon like structures. In reptiles however, since their skin is not adapted for gaseous exchange, their lungs are more developed in order to be able to satisfy their oxygen demands. The lungs of reptiles have a single bronchus running down the centre, from which numerous branches reach out to individual pockets throughout the lungs. Thes pockets (known as alveoli) greatly increase the lungs surface area and hence increase the amount of oxygen that can be absorbed from the atmosphere.
2. Cal King says:

   July 7, 2010 at 6:47 am

   Crocodilians compensate by evolving a 4 chambered heart. In the turtles, there is an incomplete wall in one of the 3 chambers, so there is less mixing of oxygenated blood and deoxygenated blood. Most other reptiles retain a 3 chambered heart they inherited from their amphibian ancestor. Therefore reptiles do not necessarily have greater stamina than amphibians. Snakes and lizards for example cannot engage in prolonged battles and must incur oxygen debt for an extra boost of energy when trying to escape. Predators often exploit this. Mongooses, for example, instinctively know that snakes can become exhausted quickly by striking repeatedly. That is why they use their quickness to provoke the snake to strike and miss.

   Personally I have used this principle to approach lizards. Despite their toadlike appearance, horned lizards can run fast enough to avoid capture. When I see one sunning on the road or in an area with sparse vegetation, I would let it sprint around while keeping an eye on it. It will soon tire and I can photograh it as it stays put because of near total exhaustion.