Facts about mammals

• Aside from monotremes, all mammals give birth to live young rather than lay eggs. The Platypus is an example of a montreme.
• Mammals have teeth that specialize in cutting and teeth that specialize in chewing and grinding.
• Mammals have a four-chambered heart.
• Placentals, the largest group of mammals, use a placenta during gestation.
• Rodentia (mice, rats, etc.), Chiroptera (bats), Carnivora (dogs, cats, bears, meat-eaters), and Cetartiodactyla (deer, goats, sheep, herbivores) make up the four largest orders within the placentals.
• The sauropsid line split into what would become modern-day birds and reptiles with the synapsid branch leading to mammals.
• The Jurassic Period saw the first true mammals while modern mammals appeared in the Palaeogene Period
• Mammals use two bones for hearing that their ancestors used for eating.
• Most mammals have seven cervical vertebrae.
• Mammalian lungs have a honeycombed structure.
• Mammalian skin is made up of three layers; epidermis, dermis, and hypodermis, however, this characteristic is found in all vertebrates.
• Mammals are the only animals with hair
• Most mammals are endothermic; they produce their own body heat.
• The training or learning a mammal experiences when it's young is diverged from its dependence on its mother.
• The ability from young mammals to learn from experience is a primary reason for the evolutionary success of the mammal.
• Some mammals are completely solitary aside during reproduction while others form complex social groups.
• Mammals evolved from four-legged ancestors.
• Aquatic mammals (dolphins, whales) have fins evolved from legs.
• There are four mammalian groups that are fully aquatic.
• Bats are the only mammal that can truly fly.
• The original purpose of lactation (milk production) is thought to have been to keep eggs moist.
• Fossils from the mid-Jurassic period, ~164 million years ago, contain the earliest evidence of fur or hair.
• Mammals are one of the 6 main classes of animals
• Nearly all mammals have what are called "baby-teeth". Some exceptions include the anteater, which has no teeth at all.
• The word mammal comes from the Latin mamma, meaning breast. This is derived from milk production in females for their young.
• All mammals are warm-blooded, which means they maintain a constant body temperature despite environmental conditions.
• The largest mammal on land, and largest animal on land, is the African Bull Elephant.
• The tallest animal on the planet is also a mammal, the Giraffe.
• There are people suffering from Agrizoophobia, which is the fear of wild animals. Can you imagine that?