Digestive System in mammals

To fuel endothermy, mammals require more calories per ounce (or gram) of tissue than do ectothermic vertebrates such as reptiles. This is accomplished by more efficient digestion of food stuffs and more efficient absorption of nutrients. This efficiency begins with specialization of the teeth. Mammals have four different kinds of teeth (heterodonty) that are ideally shaped to cut, slice, grind, and crush food. An exception is the toothed whales in which all the teeth are similar (homodonty).
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Zebra stripes evolved to keep biting flies at bay

Why zebras evolved their characteristic black-and-white stripes has been the subject of decades of debate among scientists.

Now researchers from Hungary and Sweden claim to have solved the mystery.

The stripes, they say, came about to keep away blood-sucking flies.

They report in the Journal of Experimental Biology that this pattern of narrow stripes makes zebras "unattractive" to the flies.
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Cardiovascular and Respiratory Systems in Mammals

In order to distribute nutrients and oxygen needed for metabolism, mammals need a highly efficient circulatory system. The main differences in circulatory structure between mammals and most other vertebrates are in the heart and in the red blood cells.

The mammalian heart has four chambers (as do birds and crocodilian reptiles) compared to the three chambers found in the reptiles (except the crocodilians). The additional chamber is the result of a muscular wall (or septum) that divides the ventricle (lower half of the heart) into two chambers. In reptiles there is a single ventricle in which deoxygenated blood from the right atrium mixes with oxygenated blood from the left atrium.
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Claws, Nails and Hooves: Distal Ends of Mammal

The distal ends of mammal digits possess keratinized sheaths or plates that are epidermal derivatives forming claws, nails, or hooves. Only the members of the whale and sirenia (seacows) families lack these structures. Claws are usually sharp, curved, and pointed. In many cases mammal claws are very similar to the claws found in other vertebrates. A claw consists of a dorsal plate called the unguis and a ventral plate called the subunguis.

The unguis is curved both in length and width and encloses the subunguis, which is connected to the digital pad at the distal end of the digit. In addition to protection, claws assist predator species, such as lions and tigers, in holding their prey. They provide traction for some arboreal species (e.g., squirrels) when scampering on branches. Sloths have long curved claws that serve as hooks for hanging. Digging mammals, such as anteaters and moles, have long claws that help them dig.
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Body design and skeletal system

Jaw and ear structure in mammals. Mammals have only one bone in the lower jaw, not several as reptiles do. However, the bones of the former reptilian jaw are now part of the mammalian inner ear structure.

As endotherms, mammals require more energy than ectothermic animals. Consequently, many mammal traits evolved to conserve energy. This is particularly true of the mammal skeleton. Mammals differ as a group from other living quadrupedal vertebrates in that their limbs are positioned directly below the body, allowing more energy-efficient locomotion. The lateral placement of the limbs on reptiles and amphibians requires them to spend considerable energy keeping their bodies lifted off of the ground while they undulate laterally.
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Locomotor adaptations

Mammal tail diversity reflects different functions. 1. A jerboa’s tail is used as a counterweight and balance; 2. A spider monkey’s tail is prehensile and used in locomotion; 3. A narwhal’s tail propels it through the water; 4. A mule deer’s tail can communicate an alarm; 5. A red kangaroo uses its tail as a support while upright; 6. A northern flying squirrel uses its tail as a rudder.

The musculoskeletal design of the mammalian body has accomodated many diverse means of locomotion, not only in terrestrial environments but also in aquatic and aerial niches. Many mammal species are capable of using several different means of locomotion, but much of the body configuration is determined by the dominant mode of locomotion used by a particular species.
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Colleges with Zoology Majors

If you are thinking of declaring a zoology major, you will need to work with your academic advisor to explore different educational tracks and zoology programs available at your school. Your advisor can share information about the program requirements, introductory and advanced zoology courses required, and any internship or field work needed to meet graduation requirements. Your counselor or advisor will also be able to share information about the different types of career options available for zoology majors in your state.

Most accredited colleges and universities that allow students to declare a zoology major only permit students who are at the graduate level to do so. You will need to first complete your undergraduate studies in science and related fields, and excel in natural science, biology, chemistry and other subjects. When you apply for graduate school, you will be able to take several specialized courses and elective that are directly related to zoology, animal science and research.
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Integumentary system in Mammals: Characteristics Mammalian integument

The integumentary system is composed of the skin and its accessory organs. The mammalian integument has many of the characteristics that we consider mammalian. Generally mammalian skin is thicker than the skin of other vertebrates because of its function in retarding heat and water loss. The integument consists of two major regions, the epidermis and dermis. Squamous cells are produced by a basal (or germinative) layer on the border of the epidermis and dermis. As cells are produced at the basal layer they push the cells above them toward the surface of the epidermis. As they move toward the surface the squamous cells fill with the protein keratin and produce the corneum, a tough waterproof layer of dead cells on the outermost layer of the epidermis. Epidermal cells are continuously shed and replaced as they serve as mechanical protection against environmental insults.

The dermis is mainly a supportive layer for the epidermis and binds it to underlying tissues. Blood vessels in the dermis pass near the basal layer of the epidermis and provide the cells of the avascular epidermis with nutrients. The dermis also contains muscle fibers, associated with hair follicles, and nervous tissue that provides assessment of the environment. A subcutaneous layer lies below the dermis and is a site of adipose (fat) deposition, which serves as both insulation and energy storage.
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Structure and function Mammals
Mammal foot diversity
Claws, Nails and Hooves
Head of mammals

College Zoology Education: What is Zoology?

If you've been exploring different career options in natural science, animal biology or related subjects, you may have asked yourself, what is zoology? Zoology is the study of animals, species and their behaviors. It is actually a branch of biological science that focuses entirely on the study of animals. Students enrolled in zoology degree programs typically take a variety of classes that include studying the structure of different organisms, subcellular units of life, genetics and the significance of the behavior of animals. It is both a descriptive and analytical science, and you will need to complete a doctoral degree if you want to pursue a career in research or teach after your college education.

Workers in the zoology field have a strong working knowledge of dozens of different species, but may also choose to specialize in a particular type of animal or species. If you look at a zoology description in a college handbook or on job boards, you'll find that the nature of the work is less on the treatment of medical diseases or problems, and more on just studying the nature of animals and species itself. Zoologists are ultimately biological scientists and researchers, and often make significant contributions in the field of research throughout their careers.
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Endangered Animals Information: Causes of Endangerment and Saving the Endangered Animals

Man's desire to expand rapidly has destroyed the natural habitat of wild animals, making them homeless. International Union for Conservation of Nature (IUCN) includes the red list names of over 5,000 vertebrate animals, among a total of 15,589 species, as endangered animals.

The main reason for animals endangered is the uncontrolled human activity. To pursue mindless development, man has created irreparable damages. The gases emitted from greenhouses have brought global climate change affecting everybody. Industrial wastes have polluted the river water and marine life.

Overexploitation of animals to satisfy the needs of humans has led to considerable downfall in their number. Unrestricted hunting of Whales during the twentieth-century has made them endangered animals. Poaching of rhinoceros and tigers is another serious cause of their falling numbers. Rhino horns and tiger bones are widely used in making traditional medicines.

According to IUCN, one-third of the amphibians, one-half of the fresh water turtles, one-eighth of all the birds, and one-fourth of mammals are in danger. The causes for their endangered lives are directly related to the human beings
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Health Care and Maintenance of Zoo Animals

The health and care of zoo animals is of concern to many people. Animals in modern zoos are well cared for, not only because of concern for the welfare of the individual animals themselves but also because each animal is an investment. Acquiring and maintaining any species for display or research is costly. Good food, suitable living quarters, and medical care usually...

Zoos monitor the health of their animals very carefully, because many species of animals in zoos are nearly extinct in the wild. The medical personnel at zoos are well trained in dealing with exotic species. A veterinarian at the San Diego Zoo examines a baby orangutan.