No, birds are not alike mammals. Birds belong to the avian group, but still, mammals might have particular characteristics that might overlap with some of the characteristics of birds, but that does not make them birds.
Mammals have milk glands, they have hair and fur on their body, and they are also viviparous. However, birds have none of these, rather the similarities that can be found are – that both are warm-blooded, possess vertebrates, have four-chambered hearts, etc.
So, let’s get to understand the key similarities between birds and mammals. This guide will help you to decide why birds and mammals are not alike, also you will learn about certain exceptions.
Who are Vertebrates?
In the Animal Kingdom, vertebrata is a phylum that includes all the animals and birds having a spinal cord and a backbone. Based on the characteristics, the subphylum of vertebrata can be divided into 5 classes: fish, reptile, amphibian, mammal, and bird. It has been found that 310 million years ago the mammalian and avian line was split and they evolved into the present species, so they have a very recent common ancestor.
What are Avians?
Avians can distinguish from their feathers and belong to the class of Aves. There are more than 10,000 species of birds on earth and have been classified to the class Aves. They have limited senses of hearing and smell but they have a well developed eyesight. They are mostly seen perching on tree tops or flying.
Here are the distinct characteristics of an avian:
Structure
They have a slender body, along with a backbone. Birds are warm-blooded and due to homeostasis, they can maintain their body temperature and even survive in the coldest temperatures.
Flying
They have specialized feathers that keep them insulated and help them to fly. Their features also help them to attract males during the mating season. They have lightweight wings, and hollow bones, along with structural support and air pockets which assist them in flying.
Beak
Birds lack teeth, but they have a beak which functions as a jaw. Different birds have different types of beaks based on their feeding habits.
Lay Eggs
Birds give birth to young ones by laying eggs. They have different incubation periods based on the species of birds and tend to lay 5 to 9 eggs at a time.
Exceptions
There are also many avians who cannot fly, such as ostrich, and emu, and these birds are known as flightless birds, even if they have wings. These birds basically have a heavy bone around their leg which helps them to run, instead of flying. Some birds also have scaled legs instead of features.
Who are Mammals?
Animal species that have certain particular traits are put into the mammalian group, such as bodies covered with hair or fur, they are warm-blooded, can regulate temperature, have a special mammary gland, can grow their babies inside their body, and give birth to live young ones. Also, their attributes of having a four-chambered heart, trio bones in the middle ear, diaphragm, etc, make them belong to the class Mammalia.
How Are Birds and Mammals Similar?
Looking back at the evolutionary history both these birds and mammals are connected through Seymouria, and so many similarities can be found. Here are the similarities found between birds and mammals:
Warm Blooded
Both mammals and birds are warm-blooded animals, and so they can maintain a constant body temperature. This characteristic is also known as homeostasis, where the animals do not need any external heat to stay warm. They can remain active during the cold, and survive harsh winters, without switching locations. Their calorie intake is also quite similar and it depends on the weight and necessity to stay active.
Vertebrates
Both mammals and birds have a backbone which is called vertebrae and their skeletal system is made of bones.
Heart
Both mammals and birds have four-chambered hearts and this helps them to carry out their daily work, which requires a lot of energy. Their circulatory system is effective and also keeps the oxygenated and deoxygenated blood separate, making it an efficient model.
Blood
Both mammals and birds’ bodies contain both red and white blood cells and they are known as erythrocytes and leukocytes. The red blood cells contain hemoglobin which helps in the transport of oxygen throughout the body. They also have an effective immunity system and regulation, due to the presence of leukocytes.
Breathing
Both mammals and birds have cellular respiration systems to metabolize energy which uses oxygen and water. They rely on the lungs to breathe in and out oxygen, which makes the process faster, and also the respiratory system is quite complex.
Parental Care
Both mammals and birds take care of their young ones until they become independent enough to get their food on their own. However, the length of time might vary from species to species and based on the age of the young one.
Distribution
Both mammals and birds are distributed globally. Both are considered to be widespread animals in the animal kingdom. They can adapt easily and live on the landmass of Earth. They are seen in marine, and terrestrial environments and also freezing arctic terrains, expansive oceans, and loft mountains. They can also survive in variable ecosystems, such as deserts, seas, and dense forests.
Differences Between a Bird and a Mammal
The key difference will help you to understand why birds and mammals do not fall under the same category –
Physical Difference
Birds have feathers throughout their body, whereas mammals have fur or hair on their body. Birds have wings that help them to fly, while mammals don’t (exception, a bat is a mammal and has wings). Mammals have well-structured jaws, whereas birds have beaks or bills. Birds have hollow bones, scaled legs, wishbones, and air sacs which are not found in mammals. Also, the mammalian heart is bigger than the bird’s.
Sensory Difference
Mammals have very strong senses, hearing, vision, smell, and also touch but birds do not, they only have powerful eyesight for foraging. Birds communicate through different types of vocalization, which is known as singing or calling, some birds can even mimic other surrounding sounds. However, the vocalization capability of mammals is quite less than that of birds and they mostly rely on non-vocal ways to communicate, such as body language or scent.
Food Habit Difference
Mammals have a broad diet chart as they can be carnivorous, herbivores as well as omnivores. They also have different types of teeth based on their way of having food, either tearing, chewing, grinding, or a combination of all. On the other hand, birds do not have teeth, they use their beaks and based on the type of food they feed on, the shape varies.
Social Structure Difference
Birds are social creatures, living in flocks and when it comes to mating season they form a pair, they look for a pair, whereas males are solitary creatures, come together to mate, and as the hierarchy evolves they tend to form complex social groups. Now, there are exceptions too, where some birds form monogamous pairs.
Reproductive Difference
Birds are seen laying eggs and do not carry their chicks, whereas mammals produce live young ones, and carry their offspring inside the womb, during the gestation period. Mammals also have mammary glands that produce milk for feeding the young ones, whereas birds do not produce milk as they do not have any milk glands, instead, some birds have crop milk, which is similar to mammalian milk.
Are Birds Close Relative to Reptiles?
There is a close relationship between birds and reptiles as they share a recent common ancestry history with dinosaurs. Dinosaurs are believed to be a reptilian form which later on evolved, became diminished in size, and developed feathers that turned out to be the modern birds.
