Diversity

There is great variety among mammals, and in this chapter we try to show you some representatives of the most outstanding differences among them. For example, here you will discover that there are species, such as bats, that are expert fliers, while others, such as dormice, enter into a deep winter sleep that allows them to save energy during that when food is scarce. Here, We will also show you how the bodies of some mammals (whales and dolphins) are adapted to aquatic life. In addition, we will consider the ability of certain mammals to adapt the hot and dry conditions of the desert. Cammels in particular, are very adept when it comes to retaining and effeciently using liquids.

Deep Sleep

How many times have you heard the expression 'dead as a dormouse'? The comparison is no accident, although it should be understood that dormice do not die: They merely hibernate. In the cold season, low temperatures and scarcity of food lead many mammals to enter into lethargic states. Body temperatures drop, heart rates and respiration slow down, and they lose consciousness.

Record Breath-Holders

Sperm whales are unique mammals whose species is remarkabale for many reasons. On the one hand, they have the ability to dive to a maximum depth of 3,000 m(9,800 ft) and remain underwater without oxygen up to two hours. They are able to do this by means of complex physiological mechanism that, for example, can decrease their heart rate, store and use air in the muscles, and prioritize the delivery of oxygen to certain vital organs, such as the heart and lungs. Thye are the largest whales with teeth, which are found only on the lower mandible.

Aerial Acrobatics

Cats have a surprising ability to land upright. The secret lies in their skeleton, which is more flexible and have more bones than that any other mammal. Cats' reflexes allow them to twist using the physical principle of the conservation of angular momentum. The principle, first formulated by Isaac Newton, states that all bodies in circular movement tend to use a constant amount of energy. Thus, the more the animal extends its legs to its axis of rotation, the slower it rotates, redistributing, the total energy of the system. If the animal tucks in its legs, it rotates more rapidly.

Natural Builders

They have no bricks or cement, but beavers, semiaquatic rodents, skilfuly managed to build lodges of great architectural beauty. They do not work along, and it is usual for them to act in family groups. Everyone collaborates in building the home, which is generally located next to a river or lake surrounded by forested areas and which can be entered only through aquatic tunnels. The task is difficult, and beavers work their whole lives enlarging, repairing and improving their dwelling.

Nocturnal Flight

Bats are the only mammals that can fly. Scientist call them Chiroptera, a term derived from greek words meaning 'winged hands'. Their forelimbs have been transformed into hands with very long fingers joined together by a membrane (called the patagium) that forms the surface of the wing. These mammals' senses are also sensitive that they can move and hunt quickly and accurately in the dark.

Playing Hide and Seek

Just like species of the animal kingdom, some mammals that live in the wild rely on their body's colourations or appearance to disguise their presence. Some mammals imitate objects in their environment, and others take on the appearance of other Animals. Zebras' stripes, for example, give these animals a very showy appearance - but when moving in their natural environment, zebras are camouflaged. Some differentiate between mimicry and crypsis, which the natural ability to go unnoticed without requiring any associated behaviour. In other cases, however, the forms and colours of camouflage would be useless if they were not accompanied by some kind of imitative behaviour.

The Language of Water

The ways in which cetaceans communicate with others of their kind are among the most sophisticated in the animal kingdom. Dolphins for example, click with their mandibles when in trouble and whistle repeatedly when afraid or excited. During courtship and mating, they touch and caress. They also communicate through visual signals - such as leaping - to show the food is close by. They have a wide variety of ways to transmit importa