Unseen Passage for Class 3 - Passage 11

Passage - A mammal is an organism that inhales air, possesses a spinal column, and develops fur at some point in its life cycle. Additionally, all female mammals have glands capable of producing milk. Mammals rank among the most intelligent of all existing creatures.

Mammals encompass a diverse array of creatures, ranging from cats and humans to whales. There are over 5,000 species or types of living mammals, with rodents, including mice and squirrels, constituting more than half of this group.

Mammals inhabit various major environments across the globe. The majority of mammals reside on land—whether on the ground, in trees, or underground. Some mammals, like otters, beavers, and seals, inhabit both land and water. Whales, dolphins, and manatees are mammals that spend their entire lives in water.

Mammals vary in size, from a diminutive bat to a colossal whale. The Philippine bamboo bat weighs only about 0.05 ounces (1.5 grams). On the other hand, the blue whale, Earth's largest animal, can exceed 100 feet (30 meters) in length and weigh up to 200 tons (180,000 kilograms).

Bats and whales, though atypical mammals, possess distinct characteristics. While most mammals have four legs for terrestrial locomotion, bats have two wings for flying and two hind legs for grasping. Whales have two flippers and a tail for swimming.

Mammals are unique in their ability to produce milk for nourishing their offspring. The female possesses specialized glands known as mammary glands. Following childbirth, the mother's glands produce milk, which she uses to feed the young until they are self-sufficient.

All mammals exhibit hair during some stage of their development, providing insulation for the body. The color and pattern of the hair may aid a mammal in blending with its surroundings, offering a means of concealment from predators. In certain mammals, such as porcupines, hair transforms into hardened spines. Specialized hairs, like a cat's whiskers, are highly sensitive to touch.

Mammals are warm-blooded, maintaining a relatively constant body temperature regardless of external conditions. This adaptability enables mammals to inhabit diverse climates.

Lastly, mammals possess a highly developed brain, recognized as the most intricate organ. This sophisticated brain allows mammals to learn from experiences and adjust their behavior accordingly.