Answer. Mammalians are characterised by some typical mammalian features. Such mammalian features include the presence of mammary glands in the female for feeding the young ones. The bodies of mammals are covered by epidermal hair. Generally, mammalians are exothermic and warm-blooded. They are generally tetrapods. The presence of pinna is a piece of major information about mammals. Their body consists of two types of glands: sweat gland and sebaceous gland, their endoskeleton is generally made up of bones. The most unique feature of Mammalians is their heart is four-chambered. It ensures a clear separation between oxygenated and deoxygenated blood. Mammals show internal fertilisation. Mammals are generally viviparous where the foetus is nourished by the mother through the placenta. Another salient feature of class mammal is the absence of a nucleus in red blood cells. The thorax and abdominal cavity are separated by the diaphragm.