Is a bird a mammal? If you’ve been reading the articles in our mammals section, then you’ll know the answer to this question!
Are Birds Mammals?
The answer to ‘Is a bird a mammal?’ is NO; a bird is NOT a mammal. On this page, we’re going to find out why!
A bird is a member of Aves, a group of animals in the animal kingdom. All of the members of this group have certain things in common. These shared characteristics are what make birds birds. If an animal doesn’t have all of these characteristics, then it belongs in a different group.
Likewise, a mammal is a member of a group of animals called Mammalia. To be a member of Mammalia – and therefore to be a mammal – an animal must have certain characteristics.
Although there are some similarities between birds and mammals, there are also many differences between the members of each group. Read on to discover what those differences are …
Both Aves and Mammalia are ‘classes’ of animal. A ‘class’ is one of several groups that scientists sort living things into. This process is known as ‘animal classification’.
Within a class, animals are further sorted into groups of animals that are even more closely related to each other. You may have heard of people talking about an animal ‘family’. An animal family – such as Canidae, the dog family – is a subgroup of animals within a class.
Animals are sorted depending either on their physical characteristics or on their family tree (which usually – but not always – amounts to the same thing).
The characteristics shared by animals within the Aves (bird) class are different to those shared by the animals in the Mammalia (mammal) class. This, in a nutshell, is why a bird is not a mammal.
However, there is some overlap between the characteristics of birds and mammals. This is where the confusion arises.
Let’s look at the differences (and the similarities) between birds and mammals.
Birds Vs Mammals
Similarities Between Birds and Mammals
Although birds and mammals are very different types of animal, they do have certain characteristics in common:
- Vertebrates: both birds and mammals are vertebrates, which means that they have backbones.
- Endothermic (warm-blooded): both birds and mammals are endothermic (warm-blooded). This means that they are able to regulate their own body temperatures. For example, warm-blooded animals are able to warm themselves up when cold (e.g. by shivering); they don’t need to move to a warmer location or bask in the sun like cold-blooded animals).
- Four-chambered hearts: the hearts of both birds and mammals have four-chambers. This is a more efficient system than the three-chambered hearts of amphibians and most reptiles.
The Differences Between A Bird and A Mammal
Although they share certain characteristics, birds and mammals are very different animals. Let’s find out why.
A member of the Aves class (i.e. a bird) has the following basic characteristics that are not shared by mammals:
- Feathers: birds’ bodies are covered by a number of different types of feathers. Feathers help with flight, and also with insulation (keeping the bird warm).
- Beaks and no teeth: birds don’t have teeth, and have to swallow their food whole, or cut it up into manageable bits with their beaks. A bird’s beak is often highly-specialised according to its diet.
- Egg-laying: all birds lay eggs with hard shells. Some mammals (called monotremes) lay eggs, but monotreme eggs have softer shells, similar to those of many reptiles.
A member of the Mammalia class (i.e. a mammal) has the following basic characteristics that aren’t shared by birds:
- Hair: mammals are the only group of animal to have hair; if an animal has hair, then it’s a mammal!
- Give birth to live young. All mammals – apart from the five monotreme species – give birth rather than laying eggs.
- Feed their young with milk. All female mammals feed their young with milk. This highly nutritious liquid is produced by structures called ‘mammary glands’, from which mammals get their name. No other type of animal can produce milk.
You can find out more about what makes a mammal a mammal here: What is a Mammal?
Bird Adaptations For Flight
Being able to fly is not a defining characteristic of birds: bats are mammals, and they can fly. Some reptiles and amphibians too can glide (although strictly, this isn’t flying).
However, all birds – even flightless birds such as penguins and ostriches – are descended from animals that could fly, and their bodies reflect the adaptations required for flight.
The most obvious adaptation for flight is a bird’s wings. They are the bird’s forelimbs. By flapping their wings, most birds can take off, glide, and power themselves through the air.
Most birds have lightweight, hollow skeletons to aid flight. Birds have high metabolisms (the amount of energy required to live), and have to eat large amounts of food. This is mainly because flying requires a great deal of energy.
In addition to lungs, birds have a number of air sacs inside their bodies. This helps to move air in and out of a bird faster. This too is a necessity due to the high metabolism of birds.
Is A Bird A Mammal: Conclusion
On this page we’ve looked at the differences between birds and mammals. We’ve found that Aves and Mammalia are both classes. We’ve found that a member of Aves is a bird, and that a member of Mammalia is a mammal. We’ve also looked at the differences (and similarities) between birds and mammals.
So, the next time that someone asks you ‘Is a bird a mammal?’, you’ll be able to say ‘No, a bird is NOT a mammal!’.
Other mammal pages:
- Mammals: An Introduction
- What Is A Mammal?
- Types of Mammal
- Mammal Evolution
- Are sharks mammals?
- Is a dolphin a mammal?
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