Are Chickens Mammals or Birds?

“Do you think chickens are mammals? Some may respond, “That’s simple stuff – they’re not.” However, making the effort to know the small things about your chickens helps you understand them better. and you’ll be able to get helpful information to help flock owners raise them better.

This article will cover

  • What are Mammals?
  • Mammals and Their Characteristics
  • Revisiting Characteristics of a Chicken
  • In What Class do Chickens Belong?
  • The Animal Class Aves

What are Mammals?

are chickens mammals

Mammals are relatively famous in the list of classification for animals as it includes the most intelligent species, humans. Creatures from the class Mammalia are a group of vertebrate animals, meaning having a backbone.

The most notable feature for mammals is their process of feeding their young ones milk. These animals have a unique feature called “mammary glands,” which is also the inspiration for the name of the class, which is Mammalia.

The more modern term mammal is from its scientific name Mammalia. This word was coined by a scientist named Carl Linnaeus, which you may have heard at school when you were younger.

This term was coined in 1758 and was derived from the Latin word “mamma,” which means “teat.” Teat refers to the nipple of the mammary glands found in mammals. This is where the babies or the young ones get their milk by means of sucking.

Mammals and Their Characteristics

One of the most specific characteristics every mammal has is the mammary glands. However, there are still other characteristics that set them apart and group them into the class Mammalia.

In terms of physical appearance, One example is hair. Hair is a standard feature found in many mammals. Their hair can grow during different occasions and times during their lifetime. These hairs can be very different depending on the animal. In other words, they can take various forms. Here are some of them.

  • Thick fur
  • Defensive quills
  • Whiskers
  • And yes, even Horns

The hair found in a mammal’s body is not only for display, but they serve as something more substantial. Fur and hair are known to keep these animals warm, and they act as the primary insulation part of the animal’s body.

Their body hair also protects an animal’s sensitive and delicate skin. The hair serves as a coat of protection from things that can harm or irritate the skin. Mammals’ fur also functions as camouflage. Animals use this technique to protect themselves from predators and to prey on their future meals.

Camouflage is the art of blending with the surroundings through the animal’s appearance. Mammals like zebras and giraffes utilize these features to keep themselves safe, and belong and for their survival. The fur on mammals can also be vital in their mating processes. In this case, their fur becomes essential for their collective survival as species.

The hair growing in mammals can also function as sensory feedback. Whiskers, for example, work as sensory feedback to some animals. A specialized coat termed vibrissae works as a sensory organ, usually for nocturnal ones.

Modified hair, for example, the quills of porcupines, also function as defense mechanisms for animals. It protects the animal from potential predators and, at the same time, intimidates its possible prey.

One of the main characteristic of the “What makes an animal a mammal” show is the mammary glands. The word mammal itself refers to having mammary glands produce milk for the animal’s offspring. This is one of the main indicators for you to know whether an animal is a mammal or not.

Revisiting Characteristics of a Chicken

Now, let’s dissect the characteristics of chickens to determine which class they belong to.


Chickens come in different colors and different patterns. All of which relate to their genetic structure. Their structure depends on their parents and their parents’ genes. In simpler term, their breed is an essential factor in determining their feather’s colors.

Usually, adult males can have different feather patterns and structures from female ones. The differences are pretty evident, especially as they grow up. Tail feathers are much longer for males than for females. It creates a more intimidating look in contrast to how hens look.


are chickens mammals

Beaks are one of the most essential parts of a bird, and so they are for chickens as well. Their beaks have many functions and purposes in their lives. This serves as their mouths that enable them to intake food, teeth that give them the capacity to break down things and food before swallowing, and for protection to scare away predators or rivals as well as their weapon during fights.

Comb and Wattles

The comb and wattles are some of the remarkable features of chickens. They are usually red and stand out, so they are very noticeable. Also, these features are found in the upper part of the chicken’s body, specifically their heads. The comb and wattles are believed to serve as temperature regulators, and the ones responsible for helping chickens cool their blood.

Feet and Claws

is a chicken a mammal

Another prominent feature in chickens is their feet and their claws. These bad boys are not only used for walking but, like their beaks, are also used for protection and fighting. Another thing about their feet and claws is their process of finding food. As you may be familiar, chickens love to claw the ground for food.


Chickens’ vocal expressions are very much distinguishable from other animals. In fact, roosters have made their way up the throne of fame with their crows, especially in the morning. While hens do not crow, they also have their own distinct sounds. One example is the sound they make when they are in their egg-laying stages.

In What Class do Chickens Belong?

Now that we’ve established the essential characteristics of chickens, it can be concluded that they are not mammals. Having missed most of the criteria of the class Mammalia, chickens are not mammals.

Animals under the class Mammalia often have body hair in the form of fur, whiskers, etc., which a chicken does not possess. A remarkable and vital feature as well for mammals is their mammary glands, in which these animals produce milk to feed their young ones. Again, this essential feature is missing in chickens.

So, where do chickens belong? Chickens belong to the kingdom Animalia under the animal class Aves. Aves is the bird class. Chickens are birds, and they exhibit the typical characteristics of birds: feathers, beaks, and wings.

There is still an ongoing debate about the scientific name of chicken. However, some strongly believe that they are just the domesticated version of the wild red jungle fowl or Gallus gallus.

are chickens birds
red jungle fowl

On the other hand, others classified domesticated chicken as just a subspecies of the wild red jungle fowl and gave it the scientific name G. gallus domesticus.

The United States Department of Agriculture (USDA) accepts and considers G. domesticus as the scientific name for a domesticated chicken. Nevertheless, despite all the debates and all the suggested scientific terms, chickens ultimately belong to the same kingdom, phylum, class, order, family, and genus.

The Animal Class Aves

Birds and one specific example, the chicken, belong under the class Aves. To sum it up, and in other words, Aves is the “bird class.” The creatures under this class are all of those that share the common characteristics of birds, one of which having feathers. This class has over 10,000 species under it. This class is known for its distinct features, including.

  • feathers as mentioned earlier
  • toothless beaked jaws
  • Four chambered heart
  • High metabolism
  • Strong and lightweight skeleton
  • Forelimbs modified into wings
  • Developed flight muscles
  • Last but not least, laying hard-shelled eggs
is a chicken a bird

Unlike mammals, they do not feed their young with milk, and they do not have the specific feature to do that, which is the mammary glands.

This class is also classified into two groups, namely Archaeornithes and Neornithes. Archaeornithes is the category for extinct birds. This classification of birds is those that have teeth and a lizard-like tail. Some examples of this are Archaeopteryx and Archaeornis.

Neornithes, on the other hand, is the class where birds that have no teeth and short tails fall in regardless of them being extant or extinct. Some examples of Neornithes are the familiar birds like ducks, kingfishers, penguins, etc.

Although they are warm-blooded vertebrates like mammals are, they are more related to reptiles rather than mammals. Birds are more closely related to dinosaurs because they branched out from millions of years ago. Dinosaurs are the very first group of reptiles to have inhabited the Earth. And so, on a linear scale, birds would appear closer to the reptilian side.


So, to clarify, chickens are not mammals; they belong to the animal class Aves. They are birds and are under the animal class Aves. Reading and finding out about chickens and their class is not just about gaining knowledge for flock owners. It is also establishing a firmer relationship with their flock.

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