The basic definition of a mammal is a group of animals with backbones, whose bodies are insulated by hair and contain sweat glands, nurse infants with milk from mammary glands and have a unique jaw articulation. However, mammals are remarkably diverse and range from the tiny Kitti’s hog-nosed bat weighing 1.5 grams (.05 oz.) to the blue whale weighing in at up to 136000 kg (300000 lb).   There are more than 4,000 species of mammals across the globe. Their adaptations to their environment are unique and they inhabit every continent and every ocean in the world. Mammals are able to regulate their body temperatures since they are endothermic or “warm blooded” which means they control their body temperatures internally. return to main index