While this may seem, look, and feel like a fundamental question, many netizens ask it genuinely. So, I saw the need to answer the question extensively to reduce the traffic. YES – the dog Is a mammal. If you list all the key mammalian features, you will realize that the dog checks all boxes. To exemplify, a dog can produce milk, a prismatic enamel, a diaphragm, a hinged jaw joint, one-time tooth replacement, bones in the middle ear, and warm-blooded metabolism.
This article will look at all the emboldened items and give you a further explanation of how mammalian dogs are. After reading a little about the dog as a carnivore, the discussion will extend to mammals as a unique group of people. Then, the article will finish off with an explanation of mammalian behavior. Let’s see what’s in store!
The Explainer: Why A Dog Is A Mammal
Their Females Can Produce Milk
Like most mammals (except a few), dogs can produce milk. While this may not be an exclusive mammalian feature, it sets the canine right into the category. Bitches (or female dogs) have two chains of teats on their bellies, that is, under their bodies. The chains of teats are parallel to each other and extend from the middle of the dog’s abdomen to the back of its legs. When the female is pregnant, the teats enlarge and become more conspicuous. By the time the dog delivers its pups, there are mammary tissues behind the teats engorged with milk. Since a litter of puppies comes in multiples, the little ones suck on the teats until weaning is complete.
The dog’s mammary gland is a type of exocrine gland, which, by extension, falls under the category of secretory glands. The others that fall under the exocrine gland category include mucous, sweat, and salivary glands. Basically speaking, the mammary gland is a special type of sweat gland.
Their Jaw Joints Are Hinged
This is another distinguishing feature that sets dogs aside and puts them in the mammalian class. As compared to other animals like reptilian snakes, the dog cannot disarticulate its jaw open to widening its mouth. This cannot happen because the jaw is jointed, or simply, it has joints. The technical name of the joint in the dog’s jaw is known as the temporomandibular joint, often known as the TMJ joint. To palpitate this joint, you should feel the point on the dog’s head below the ears.
The Canines Have Bones In The Middle Ear
This is yet another exclusive mammalian feature that takes dogs with it. If you are in love with canine anatomical studies, you know that the dog’s is a great fascination. The same bones are found in the middle ear of human beings. They go by the name stapes, malleus, and incus.
The bones work together to transmit sound waves into the dog’s brain so that they are interpreted. First, the incoming sound particle goes through the ear canal. Then, it hits the eardrum (or the tympanic membrane), where it vibrates. Then, the three ear bones help transmit the incoming vibration information to the CNS, or the Central Nervous System.
The information that gets to the dog’s brain is then interpreted into what the canine consciously understands as instructions and words. That is what gets a dog obeying whatever you tell it.
The Canines Experience Tooth Shedding And Replacement
The other mammalian feature brings teeth to focus. Many mammals are born with baby teeth, and then in one developmental task, those teeth are lost. By the time the dog is around six months, all the teeth it was born with are usually gone. After the six-month mark, the adult teeth come and stay for an entire lifetime.
During the dog’s life, its teeth may either fall out or break because of injury. Like many mammals, those teeth are not replaced by others. Fishes like the shark experience the regular replacement of their adult teeth. Your dog may stay toothless for the rest of its life.
The Canine Teeth Are Enameled
Saying that a dog’s teeth are enameled means that they have an enamel, which is the hard covering of a tooth. This feature is exclusive for mammals, and since dogs’ teeth have enamels, the canines are truly mammalian. The function of the enamel is to give strength and hardness to the teeth.
Dogs Have This Mammalian-Specific Feature: Occipital Condyles
At the back of the dog’s skull, you are likely to notice two structures that look like bulbs known as occipital condyles. These are the structures connecting to the vertebrae. While each animal species has different anatomies, most mammals have two bulb-like structures, including dogs.
As Part Of Their Respiratory Systems, Dogs Have Diaphragms
For many mammals, the diaphragm plays a very pivotal role in inhalation and exhalation. The muscles making up the diaphragm experience contraction and pull air into the lungs through the trachea. When it relaxes, air moves from the air sacs and outside through the bronchioles and trachea.
As a mammalian-specific organ, the diaphragm is a type of muscle that forms the boundary between the abdominal cavity and the thoracic cavity.
Dogs Are Warm-Blooded
This is a key feature that helps people to draw the line between creatures. The inside metabolism of a mammal is not affected by the changes in temperatures. For example, the cold winter means that mammals will either be shivering or getting goosebumps. Hot weather will get dogs panting. These are mechanisms developed by the body to ensure that a mammal’s body’s temperatures remain optimum for proper functionality.
Cold-blooded creatures like snakes need to move to warmer areas when the cold comes. Also, they need shades when the days are a little too hot.
A Run-Down On Dogs: Mammalia, Carnivora
As already established, exemplified, and agreed, a dog is a mammalian creature part of the Carnivora order.
Looking at the history of dogs, you will discover that the tale is old. There are records of dog-human interactions dating back to the start of civilization. It is believed that the domestication of dogs happened around 15,000 years ago. Novel evidence has it that dogs were initially domesticated in East Asia, maybe China. With time, the canine has immensely developed, and now, there are many breeds with different characteristics.
Like humans, dogs have impressive social skills. That feature makes it easy for humans to train, play, and live with the canines. Also, that characteristic has made dogs fit in the interspecies friendship bracket.
Dogs show a lot of devotion and unmatched loyalty, all of which are born of their instincts. Dogs, which are pack animals like wolves (their ancestors), operate in the same human values of friendship and love. This makes it very smooth for dog owners to see the canine as fully-fledged members of their families.
Its scientific name is Canis familiaris, and the dog is part of the Canidae family. Depending on the specific breed, dogs have different sizes, temperaments, appearances, and functions. One dog can be as tiny as 1.5 pounds, while another can weigh a whopping 200 pounds. There are around 138 dog breeds that a recognized with respect to a country.
In human spaces, dogs fill various roles. Many times, they get the proper training to make them working dogs. If a dog does not have a traditional job, its owner can toss it into the world of sports to showcase its natural talents.
Experts estimate that dogs have lived together with humans as friends, protectors, and human companions. The dog is – without argument – the most popular pet worldwide: man’s best friend. Whether you have or you lack, a dog will always be loyal and faithful to you – it will love you to bits.
If you take a dog as a pet, it will find it easy to fit into the family. As extra members, dogs need grooming, feeding, bathing, and veterinary care. To show happiness, dogs go on wagging their tails happily. If you tell it off or scold it, the dog will sulk.
To have a dog with impressive and commendable manners, you need to train it patiently and perseveringly. At any one moment, mistreatment should not cross your mind. Dogs may bite you when pursuing their defense.
If you get a large dog, you will realize that it needs more exercise. If you get a large dog such as the Great Dane, you should take it to the recreation ground, local park, or the countryside to exercise. In those spaces, it can play games and run about. Those exercises help in health and fitness.
The one brilliant thing with dogs is that they can be taught to do things. You can throw a frizz bee, a stick, or a small branch and teach the dog ‘fetch.’ Something fascinating you should know is that dogs have a lot of smell-sensitive cells in their millions – 220 million, to be exact. Some breeders have developed dogs that detect scents thanks to that physiological advantage. The information a dog detects is not entirely understood, and that has been a matter of debate. However, dogs can pick out air and ground scents.
By Extension: The Ins And Outs Of Mammals
This section seeks to step out of a dog-specific discussion and look at the mammalian category at large. For starters, a mammal breathes air, grows hair (at a point in its life), and has a backbone. As mentioned elsewhere, many female mammals have mammary glands. Of all the creatures living on the earth, mammals are the smartest.
The mammalian category includes a wide range of animals, from dogs to humans and cats to whales. At least 5000 species of living mammals exist. Of the entire population, more than half that number consists of rodents, the class that also includes squirrels and mice.
The world of mammals has impressive and noteworthy diversity since mammals live in all the available earth habitat. You will find them in deserts, deep seas, and tropical rainforests. Also, their sizes vary from one ounce (shrew) to 200 tones (whale).
What exactly makes a mammal itself – why isn’t it a bird, a fish, or a reptile? This section will bring to your attention seven characteristics that range from the shape and form of a mammalian heart to hair and fur. Now, go on and know the features that set mammals apart from other creatures.
1. Fur And Hair
At some stage of its life, a mammal will inevitably grow hair or fur on some part of its body. This is to be contrasted with the birds’ feathers and the reptiles’ scale. A mammal’s hair can take different forms that include long whiskers, thick fur, defensive quills, and surprisingly, even horns.
The hair on a mammal’s body serves several purposes: it helps to protect the skin lying delicately underneath, it insulates the animal against the cold, and it provides camouflage and covers against predators (giraffes and zebras). Also, the hair helps in sensory feedback (the whiskers of a mouse and cat). Generally speaking, the presence of fur or hair on a mammal’s surface goes together with its warm-bloodedness.
If you look at some species like dolphins and whales, you will see no visible hair on the body. Those water mammals usually have some little hair when they are a bit young. Others have some small patches on their upper lips or chin.
2. Milk Glands Are Present
As mentioned in the dog discussion, mammals have mammary glands that secrete milk. The glands are modified and have enlarged sweat glands. The glandular tissues and ducts secrete milk that young ones get through nipples. During the weaning period, the young ones get the vitamins, salts, proteins, and sugars from the milk. It is important to note that nipples are absent in some mammals. Monotremes like the platypus secrete milk through special ducts found on their abdomen.
Although mammary glands are present in both females and males, in many mammalian species, the glands only develop completely in females. The species exempted from their rule are the Bismarck masked flying fox and the Dayak fruit bat. The males of these two types of bats can lactate, and sometimes, the males help in the nursing of the infants.
3. Their Lower Jaws Have Single Bones
For mammals, their lower bone is a single piece that attaches to the skull. This bone – known as the dentary – is responsible for carrying the lower jaw’s teeth. If you look at the other non-mammal vertebrates, you will find the dentary is one of the bones forming the lower jaw and does not directly attach to the skull.
So, why is this attachment or hinging important? Mammals are gifted with a powerful bite thanks to the muscles and the single lower jaw piece. It also helps the mammals grind tough and hard vegetable matter and help flesh-eating mammals chew and cut down prey.
4. Tooth Replacement Happens To Mammals
As mentioned earlier, mammals move from milk teeth to adult teeth. This portion is supposed to take your understanding to a scientific level. First, the trait of tooth replacement that happens for many mammals is called diphyodonty. It occurs only one time in the lifetime of the mammals. When the mammal is newborn or young, its teeth are weaker and smaller than those of adults.
The mammal starts with a first set – the deciduous teeth – which fall out before the onset of adulthood. Gradually, those teeth are replaced by a set of large and permanent teeth. However, diphyodonty does not happen to all mammals – manatees, kangaroos, and elephants do not experience it.
Other non-mammal animals are polyphyodonts, and their teeth get replaced throughout their entire lives. Examples of these animals include crocodiles, geckos, sharks, and alligators.
5. A Bony Middle Ear Is A Mammalian Exclusive
You have already been brought to the attention of the stapes, the malleus, and the incus. Commonly, these three bones are often referred to as the stirrup (the stapes), the anvil (the malleus), and the hammer (the incus) because of how they operate.
The one thing interesting about this feature is that two bones – the incus and the malleus – evolved from the therapsids’ lower jaw bone. Therapsids are mammal-like reptiles who are the predecessors of mammals and lived during the Paleozoic Era.
6. Warm-Bloodedness Is Not Specific To Mammals Only
Although the implication in this article is that warm-bloodedness is exclusively mammalian, it is not. As you may already know, mammals and birds have endothermic metabolism. For modern birds, this is a trait they share with their ancestors, the meat-eating dinosaurs known as theropods, which existed in the Mesozoic Era. However, an argument may be posited that the mammals’ warm-blooded physiologies have a better utility value than those of any other order in the family of vertebrates.
The warm-bloodedness of mammals gives purpose; it is why cheetahs are fast when running, why humans write books, and why goats climb mountainsides. All the other cold-blooded animals – specifically reptiles – have sluggish metabolisms because the external weather conditions immensely influence their internal temperatures.
7. The Hearts Of Mammals Have Four Chambers
Like all the other vertebrates, mammals’ hearts have muscles that assist in blood pumping by repeated contraction. In turn, the contractions help in delivering nutrients and oxygen through the mammal’s body. While that happens, carbon dioxide – which is a waste product – gets removed.
However, it is essential to note that birds and mammals possess hearts with four chambers – the auricles and the ventricles. This setup operates more efficiently than the amphibians’ and reptiles’ three-chambered and the fishes’ two-chambered heart.
The mammalian and avian four-chambered heart works well to separate the oxygenated blood (coming from their lungs) from the deoxygenated blood returning to the lungs for re-oxygenation. This means that the mammalian body tissues only get blood that is rich in oxygen. This translates to sustainable physical activity with few rest intervals.
Penning Off: The Mammalian Behavior And All-round Specifics
Many young mammals learn most of their behaviors – for instance, hunting – from their mothers and fathers. Some young ones separate from their parents as soon as they grow up, and others stay together in groups.
Groups and individual mammals live in spaces – terrestrial, arboreal, marine, etc. – called territories. The mammals often engage in fights with other mammals (of the same species) for territories. As part of their instinctual wiring, some mammal migrates, that is, they move between areas during specific seasons.
Some mammals that include hedgehogs and squirrels hibernate during winter. Hibernation is a unique form of sleep where the temperature of an animal’s body drops.
In terms of eating, the Mammalia class includes animals that feed on a wide food variety. The mammals that eat animals – or flesh – are carnivores. They include walruses, weasels, dogs, and cats. The others that eat plants are known as herbivores like elephants, cattle, and deer. Omnivores are mammals that eat both plants and animals, including bears, primates, and raccoons.
Reproduction happens through mating for most mammals. In almost all the mammalian species, the female carries the young one in her body when mating occurs. The young one develops inside the womb or the uterus, a part of the female’s system. The mother’s body enhances the development and multiplication of cells, that is, nutritionally speaking.
The young one gets carried in the mother’s womb for a gestation period, whose length depends on the species. To put this to perspective, a pregnant hamster will stay that way for about 14 days (to weeks) while a pregnant elephant about 660 days (about 22 months).
Most female mammals deliver their babies live. When these young ones are born, they can make movements. For example, the young one of a horse starts walking hours after it has been delivered. For other mammals like rodents, their young ones are born hairless, blind, and utterly helpless.
Other mammals give birth to underdeveloped young ones; those are called marsupials. Marsupials gestate for about six weeks, and when the baby is delivered, it crawls into the fold or pouch on the mother’s belly. There, the baby stays for a few months feeding on its mother’s milk until it gains full development. Examples of marsupials include opossums, koalas, and the more common ones, kangaroos.
The only mammals that do not give birth to live young ones are the echidnas and the platypuses – these lay eggs. That is the only difference because as soon as the eggs hatch, they start suckling their mothers for milk.