Whether a bird is an animal should be easy to answer when looking at these creatures’ physiological complexity, behaviours, and life cycles. Yet, we often question whether these winged creatures with their eggs and beaks can really be animals like our cats and dogs.
Birds are animals. Birds are classified in the kingdom Animalia, which contains all multicellular eukaryotic organisms. There are nearly 10,000 species of bird and they are all animals.
There is a lot of confusion over whether birds are animals or not and this tends to come from our education and use of language. There is a difference when we talk about animals informally where we tend to separate animals and birds.
However, formally, via biological classifications, birds are definitely animals. It all comes down to how we classify Animalia in taxonomy and where birds eventually branch away from mammals in that tree. There are more similarities than differences compared to the wider variety of life on Earth. However, it is easier to focus on the differences.
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Birds Are Animals
In short, there is clearly a lot of confusion over what it means to be an animal. Birds are animals, whether we choose to call them that or not. We often label birds as separate from animals, assuming that an animal is a four-legged land-dwelling creature, but this doesn’t line up with biology and evolution. Informally, birds are not the animals that we are drawn to as children. Formally, they are chordates and strongly tied to mammals and other vertebrates as animals.
Mammalian species are most commonly land-dwelling creatures with fur and four legs, ranging from domestic pets and small rodents to big cats, grazing herbivores, and everything in between. But, we are mammals too, as are the whales and dolphins in our oceans. Mammals are also just one group of animals, which also includes birds, reptiles, and fish. To better understand what is an animal, we have to consider the hierarchy of biological classification and taxonomy.
Taxonomical Hierarchy
All life on Earth is divided into three domains. Any creature more complex than single-celled archaea or bacteria belongs in the Eukarya domain. As this relates to all life on earth that we can see, this doesn’t help much with classification at this stage.
Moving on, there is a series of kingdoms. This is where we start to see clearer distinctions in forms. These are:
- Plantae: plant life such as flowers, trees, crops, etc
- Fungi: mushrooms and fungi that have many different structures and life cycles.
- Protista: which doesn’t fall into the category of plant or fungus.
- Archaea: single-celled organisms
- Monera: Bacteria.
- Animalia: a much wider range of multicellular creatures.
Animalia species are animals, and anything that comes under this banner should be classed as such. There are various traits that biologists use to determine animals under this kingdom. One of the most important is sexual reproduction rather than the asexual approach of single-celled organisms. These complex organisms also rely on the consumption of organic material to create energy and breathe in oxygen. You also see more specialized tissues and complex nervous systems. Anything that follows these traits within the living world is an animal.
Fish, mammals, crustaceans, insects, birds, and other groups are animals. This means that there is an estimated 7 million animal species in total – humans included. With so many species, there has to be some form of further classification. That is where we next see the 35 phyla in the Animalia kingdom. Even then, birds and mammals remain in the same group of animals – the chordates. These similar vertebrates are then separated again into classes.
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Classes
It isn’t until we get into classes that we separate the birds from the fish and the mammals. The creatures that we most commonly see as animals, with their furry four-legged bodies, are Mammalia. They have mammary glands and produce live young. Birds are in the class Aves. This is where we see egg-laying animals with feathers, beaked jaws, and a light skeleton as their own class. They are still animals but distinct enough from mammals or reptiles now to have their own group. From here, it all gets a lot more specific as biologists then determine these animals by their order, family, genus, and then finally an individual species.
Why don’t we think that birds are animals?
As we follow this taxonomic tree down through the kingdoms and classes, it is easier to see how birds are indeed animals. But, there is still that common assumption that they aren’t. A lot of this could come down to our relationships with non-human animals. Animals are the cute and cuddly creatures we have as pets, watched in wildlife documentaries, and visited in zoos.
People that consider themselves animal lovers don’t always bring birds into that equation. But, the same is also true for fish and reptiles. They aren’t always seen as animals either because they don’t conform to those preconceptions that animals must have a certain number of legs, fur, and other mammalian qualities.
There is also an issue of a lack of education on the subject. When we are encouraged to learn about animals as kids, birds don’t always play the same role. We go and pet the animals and then feed the birds. The animals play at our feet while the birds fly above us in the sky. It isn’t until we start to learn more and develop interests in biology and zoology to learn more about the similarities and how bird and mammalian species are similar animals.
Both mammals and birds are animals in their own right.
There is an ongoing desire to separate humans from animals, while also assuming that the term animal only applies to mammals. But, neither distinction is accurate. What we are doing with this sort of classification is confusing the terms mammal and animal. With a greater appreciation for the similarities and traits of the Animalia kingdom, we see where birds fit in.
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