The taxonomic unit in which whales belong is not clear for most people. Some people have always classified whales as fish since they live in water and resemble fish. However, whales are not fish but marine mammals that spend their entire lives in open seas. Unlike most mammals, their lives are so adapted to water that they cannot survive on land. Whales are some of the largest animals in the world. In fact, the blue whale is the largest living animal. There are approximately 88 species of whales.
Whales are placental marine mammals classified in the order Cetacea. Mammals belonging to this group have a streamlined body, a horizontal fin called the fluke, and a blowhole on top of their heads. There are two main suborders of whales. The whales are classified into these orders depending on their feeding parts. The first suborder is the toothed whales, which are also referred to as Odontoceti. The odontocetes like the sperm whales which feed on penguins, fish, and seals and the beaked whales which feed on squid, fish, and crustaceans through suction feeding. The other suborder is the Mysticeti or baleen whales, with whales in this group feeding on planktons by filtering the planktons into their mouths using the plates of baleen.
Characteristics That Make Whales Mammals
Whales Are Warm-Blooded
Whales, like other mammals, are able to regulate their body temperature within a steady range through several internal body activities. Their body temperatures do not fluctuate with the changing temperature of their surroundings. The metabolic body activities such as digestion enable whales to regulate their body temperature. They do not need to bask or engage in activities that would help them regulate their body temperatures like most reptiles.
Presence of Mammary Glands
The presence of mammary glands is the most distinct characteristic of mammals. The mammary glands are necessary for lactation. Just like most mammals, whales give birth to live young ones. The females feed their young ones on milk from their mammary glands until they are grown enough to fend for themselves. The milk contains high-fat content which is meant to hasten the growth of blubber. The gestation period lasts about one year but most young ones are weaned around the 11th month.
They Have Hair
By their appearance, one may not realize the presence of hair on the bodies of whales. Their skin surface appears to be smooth and without any hair or fur. However, the hair is usually very sparse on their body surface, in most cases going unnoticed. The hair is more prominent on top of their heads than on any other part of their body and can usually be seen when the whales are in their fetal stage. After they are born, most of the hair is shed off. Very minimal hair remains on their body surface.
They Breathe Air Through Their Lungs
Despite living in water, whales use their lungs for breathing. Unlike fish, they do not use the gills. Whales normally come on the surface of the water to get air. They cannot get oxygen from water because they do not have gills. They use the blowholes which are located at the top of their heads to take in and expel air.