Are Whales Mammals?

When people first think of mammals, they often think of elephants, monkeys, bears, and other land-dwelling animals. However, there are many species of marine mammals as well. The class Mammalia accounts for an estimated 6,495 species!  These diverse species inhabit every terrestrial biome and every ocean around the world.

Mammals come in a great variety of shapes and sizes, and many have incredibly unique adaptations. It is hard to believe that a naked mole rat and a gorilla are related. However, as mammals, they share key characteristics that set them apart from other groups of animals such as reptiles or birds. This article will explore how mammals are different from other life on Earth, what mammals exist in our oceans, and most of all, where whales fit into this tangled web. So, are whales mammals? Let’s find out!

What Distinguishes Mammals from Other Animal Groups?

Mammals are distinct from birds, reptiles, amphibians, fish, and invertebrates in several key ways. One is that all mammals breathe air through their lungs. Mammals also have fur or hair. In some species, the hair is a conspicuous, thick coat. However, in others, it is less obvious. Although dolphins do not have a coat of fur like many other mammals, they do have hair follicles around their snout. All mammals have hair or fur in some capacity.

A third distinguishing trait of mammals is the presence of three middle ear bones collectively called the ossicles. They are located in the middle ear behind the eardrum. These bones are the smallest bones in the human body. They play an important role in transferring energy from the vibrations of the eardrum to the inner ear. Without these bones, mammals would be unable to hear.

Another important mammalian trait is the presence of mammary glands. In fact, mammals are named after the Latin word “mamma” which means breast. The mammary glands of the mother produce milk for her offspring. Except for the platypus and echidna, which lay eggs, all mammals also give birth to live young. Several other characteristics define mammals, but these are some of the most relevant.

What Are Marine Mammals?

As the name suggests, marine mammals are mammals that rely on marine ecosystems. There are four different groups of marine mammals. Cetaceans include dolphins and porpoises. Pinnipeds include seals, walruses, and sea lions. Sirenians include manatees and dugongs. Marine fissipeds include polar bears and sea otters.

Cetaceans and sirenians spend their entire lives in the water, however they must surface to breathe periodically. Pinnipeds live mostly in the water, but they do come ashore to give birth and rest. Marine fissipeds spend most of their time on land. However, they also spend time in the water hunting.

Are Whales Mammals?

Whales are mammals. In fact, the blue whale is the largest mammal and the largest animal to have ever lived. A blue whale typically weighs 220 tons, or 440,000 pounds. Whales are classified as cetaceans, which include 89 species of closely related whales, dolphins, and porpoises. There are species of whales inhabiting all of the world’s oceans and even species of whales that inhabit deep-sea ecosystems.

All whales have typical mammalian characteristics. Whales give birth to live offspring. Female whales carry their offspring in their wombs until maturity, then give birth to the calves in the water. The calf is typically 1/4 the size of the mother whale. Once born, the mother guides her baby to the surface to take its first breaths of air. They have mammary glands, lactate, and nurse their young.

Whales all have hair follicles, although most do not grow and retain hair. They also have the three middle ear bones typical of mammals. Whales breathe air as well. However, they are able to stay under water for long periods before needing to resurface. The sperm whale can stay under water for up to two hours.

Whales’ Conservation Status

Whales have varying conservation statuses depending on the species. Of cetacean species, seven are vulnerable, 11 are endangered, and five are critically endangered. Species of whales that are endangered include some populations of the killer whale, Mediterranean sperm whale, and blue whale.

Killer whales are apex predators, meaning no other animals prey on them. However, they can occasionally be threatened by other orcas or human activities. As such, they are a keystone species and have a very important ecological role that will leave their ecosystem vulnerable to collapse should they become extinct.