Difference Between Reptiles and Birds

Reptiles vs Birds

Reptiles and birds are two important groups of animals. The morphology of these animals is very distinctive, but much of the physiology is similar. However, the ecological significances are very high with important roles being done by both reptiles and birds, but those are different roles varying depending on the species and situations, as well. It would be important to go through the presented information in this article, as it discusses both reptiles and birds in a nutshell with the most important and the interesting facts.


Reptiles belong to the Class: Reptilia with a history that dates back to about 320 million years from today. Both mammals and birds originated from reptiles and amphibians gave rise to them. There are about 8,000 species of reptiles in four different taxonomic orders known as Squamata (snakes), Crocodilia (crocodiles and alligators), Testudines (turtles), and Sphenodontia (tuatara). Snakes are the most diversified group among these four with about 7,900 species. Turtles rank the second with about 300 species, and there are 23 crocodile species and 2 tuataraspecies from New Zealand. Reptiles are cold-blooded animals with scaled skins and they lay shelled eggs. However, some of the snakes do not lay eggs but give birth to offspring. They have limbs except for the snakes, and some python species have rudimentary legs indicating that they evolved from tetrapods or legged animals. Currently, reptiles live in all the continents except Antarctica. The reptiles are highly adapted to conserve water in their body, and they absorb all the water in their food before defecation. Unlike mammals, reptiles do not chew their food, but swallow it, and both mechanical and chemical digestions take place in the stomach. All the reptiles are carnivorous, but some of the prehistoric dinosaurs were both carnivorous and herbivorous.


Birds are warm-blooded vertebrates of the Class: Aves. There are about 10,000 extant bird species, and they have preferred the three-dimensional aerial environment with great adaptations. They have feathers covering the whole body with adapted forelimbs into wings. The interest about birds elevates because of some specializations seen in them viz. feather-covered body, beak with no teeth, high metabolic rate, and hard-shelled eggs. In addition, their lightweight but strong bony skeleton made up of air-filled bones make easy for the birds to be airborne. The air-filled cavities of the skeleton connect with the lungs of the respiratory system, which makes it different from other animals. Birds are more often social animals and live in groups known as flocks. They are uricotelic, i.e. their kidneys excrete uric acid as the nitrogenous waste product. In addition, they do not possess a urinary bladder. Birds have a cloaca, which has multi purposes including excretion of waste products, mating, and laying eggs. Birds have specific calls for each species, and they differ with the mood of the individual, as well. They produce these vocal calls by using their syrinx muscles.


What is the difference between Reptiles and Birds?

• Reptiles belong to the Class: Reptilia while birds belong to the Class: Aves.

• Reptiles have scales all over the body, whereas birds have scales on the legs and the rest of the skin is covered with fluffy feathers.

• All the present-day reptiles are carnivore, but birds have many different types of food habits.

• The forelimbs of birds are developed into wings, while most of the reptiles (7,900 species out of all the 8,000 species of reptiles) do not even have legs.

• Reptiles could be lightweight as well as heavyweight, whereas birds usually lightweight animals but sometimes there are heavy ratite species, as well.

• The diversity is higher among birds than reptiles.

• There are different shapes of body types in reptiles, but it is always streamlined shape in birds.


  • Dave McDonald

    All present day reptiles are carnivores????? Who wrote this?

  • S. Sivakumar

    There are only around 3000 snakes in the world, not 7,900.