Unusual and Little-known Facts About Mammals

Fact about African elephant the largest mammal
Mammals are a class of vertebrates (animals which have a backbone) which began to evolve on Earth around 200 million years ago. The largest mammal on land is the African elephant. It can grow up to 3.3 meters in height and weigh around 13,000 pounds. The distinction of having the longest gestation period of 22 months is also held by elephants.
Mammals are defined by some basic characteristics that all of them share. Mammals are endotherms, which means that their bodies can generate heat in order to maintain a suitable body temperature. They have mammary glands which produce milk for nourishment of the young ones after they are born. Hair is another important feature in mammals and it is present on their body at least at some point in their life.
They have three bones in their middle ear. Their circulatory system is highly efficient and a four-chambered heart is one of the exceptional features of mammals. All mammals breathe air including aquatic mammals. Their lungs play an important role in the exchange of oxygen and carbon dioxide.

Though mammals share certain attributes, some of them do distinguish themselves from the crowd. All mammals have 4 legs except whales, dolphins, dugongs and manatees which have lost their hind limbs in the process of evolution. Mammals usually have 7 neck vertebrae. However the manatee and two-toed sloth have 5-7 neck vertebrae, while the three-toed sloth has 8-9 neck vertebrae.

Teeth are replaced once in the life cycle of a mammal and not continuously. The exceptions to this rule are pygmy rock-wallaby, silvery mole-rats and manatees, whose teeth are continuously replaced during their lifetime.
Classification of Mammals
Based on how their offspring develops, mammals are divided into two subclasses:

• Prototheria - These mammals lay eggs, incubate them for a certain period, after which the young ones are born. They are also called monotremes. The platypus, and the echidna are the only monotremes on Earth.

• Theria - These mammals carry their offspring in the womb for a certain period before it is born. This class is further divided into:

  • Metatheria - it includes mammals which have abdominal pouches. These are also known as marsupials. They give birth to underdeveloped babies which are then carried in the pouches till they are fully developed. Kangaroos, Koalas are some well-known examples of marsupials.
  • Eutheria - these mammals do not possess pouches and the baby is kept nourished within the body by a well-developed placenta. They are also known as placentals. About 95% of mammals belong to this group. Human beings, elephants, tigers, cows, bears are some examples of placentals.
Interesting Mammal Facts
bowhead whale
Bowhead Whale
► The bowhead whale has the longest lifespan among mammals and can live for 100 years or more.

► The largest mammal is the blue whale. It is also the biggest animal of any kind to have ever lived on Earth. It can grow to 30 meters in length and weigh around 30,000 pounds.
► Another feather in the cap for the blue whale is that it is also the loudest animal on Earth. Its call can be as loud as 188 decibels.

► The Virginian opossum, the rare water opossum or yapok of South America and the eastern native cat of Australia share the shortest gestation period of 12 days.
► The fastest mammal on land is the cheetah, which can reach speeds of up to 60 mph.

► The smallest mammal in the world is the Kitti's hog-nosed bat or bumblebee bat which grows to only 1.3 inches in length and weighs 2 grams.

► Bats are the only mammals that are capable of flying.

► The fastest mammal in water is the killer whale, which can swim at speeds of 34 mph.
Map of Australia
► The Australian continent is the only place in the world where all three major classes of mammals are found i.e. monotremes, placentals and marsupials. It is also home to around 70% of marsupial species on Earth.

► There are certain mammals that do not have any teeth such as platypus echidna, Baleen whales(which include 15 species), and anteaters.

► 12% of mammal species are found in Indonesia, which is the largest for any country.

► Monotremes are only found on the Australian continent.
Today there are about 2500 species of mammals in the world, however human beings have perhaps become the most dominant species. Mammals have evolved over centuries to be able to thrive in all kinds of environment and are one of the most diverse inhabitants on the face of the Earth.