EVERYDAY SCIENCE

Detailed explanation-1: -Reptile hearts have three chambers, two atria and one ventricle (Figure 1). The exception is crocodilians, which have four-chambered hearts, just like mammals and birds.

Detailed explanation-2: -Amphibians and reptiles (except for crocodiles) contain a three-chambered heart with only one ventricle. This is because these animals have a slower metabolism rate and hence, they require a lower amount of oxygen per liter of blood to be delivered to the body.

Detailed explanation-3: -Most reptiles have two atria and one ventricle. The only exceptions are the 23 living species of crocodilians (alligators, caimans, crocodiles and gharials) who, like birds and mammals, have four-chambered hearts with two atria and two ventricles (Jones, 1996; Jensen et al., 2014).

Detailed explanation-4: -Turtles are a curious transition–they still have three chambers, but a wall, or septum is beginning to form in the single ventricle.

Detailed explanation-5: -The salamander is an amphibian with a three-chambered heart. It has two atria and one single ventricle. These animals also have separate or different blood vessel circuits for oxygenating and delivering blood.