Cat, Rat and Bat belong to same class Mammalia, phylum Chordata. The common characters of these animals are (i) Hair; (ii) Mammary glands; (iii) Integumentary glands, e.g., sweat glands; (iv) Seven cervical vertebrae; (v) Diaphragm; (vi) Four chambered heart, (vii) External pinnae; (viii) Vivipary.