MammalsMammals
• MAMMALS• Kingdom Animalia• Phylum Chordata• Subphylum Vertebrata• Class Mammalia
• There are about 5000 species of living mammals.
• Approximately 300 species are considered endangered, including most cetaceans, cats (except domestic cats), otters, and primates
(except humans).
• Mammals – 3 subclasses – based on the way they reproduce
• Subclass Prototheria –Order Monotremata – lay eggs w/leathery shells and nourish the young with milk from belly pores; Examples spiny anteater and the duck billed platypus;
MonotremataMonotremata
4 species of echidna- spiney anteaters
Platypus
SEE VIDEO!
• Subclass Metatheria - Marsupials;
• Short period of time inside mother, young then partially develop in mothers pouch; About the size a of a grain of sand when born, then climb to pouch.
• Example kangaroo, Tasmanian devil, wombat, opossum, koalas
http://www.parks.tas.gov.au/wildlife/mammals/devil.html
Wombat
Tasmanian Devil
Koala
Kangaroo- video
• What animal goes on a honeymoon, and 13 days later gives birth? • It lived during the age of dinosaurs: fossil remains have been found from 70
million years ago. • It can eat almost anything.
• It loves to eat insects (beetles, cockroaches, and so forth).It eats snails and slugs.It catches and eats roof rats.It also eats cat food, dog food, people food.
• It has thumbs on its hind feet! • It is very quiet, although it can make some sounds. • Learning and discrimination tests rank it above dogs, and more on the level
of pigs. • Give Up? More clues...
It does not have a territory, but is always on the move, going to wherever the food is. Females stay in a smaller area while they care for their young.
• It puts up a terrific bluff if cornered and can give the appearance of being really good at defending itself. NOTE: it is not good at defending itself!
• Big Clue!• If attacked and unable to fight or run from danger, it collapses and
appears to be dead!
An Opossum!
• Subclass Eutheria – Placental animals; carry young inside uterus until birth; 17 orders;
• Only suborder evolved to be found on land, sea, and air;
• 95% of all mammals are
placental.
• What is a mammal?• Mammary glands – produce
and secrete milk to nourish the development of the young.
• Diaphragm – domed respiratory muscle between thoracic and abdominal compartments; allows large oxygen intake.
• Hair – long, slender filament; thought to have evolved from scales; provides insulation by retaining heat, provides waterproofing, camouflage, communication w/other animals, and protection.
• Endothermic• 4-chambered heart• specialized teeth – example –
beaver (incisors), wolf (canines), horses (molars and premolars)
• highly developed nervous system and senses; more folds in brain provides more surface area.
• Glands – cells or group of cells that secrete fluids;
• Appendages modified for food gathering in their habitat. Example – primates have an opposable thumb;antelope have strong, slender legs for fast running
• Have a single jaw bone• 3 middle ear bones
• HAIR AND OTHER DERIVATIVES
• Pelage – coat of hair• 2 types of hair • 1. guard hair - coarse,
longer hair; protects against wear and may provide coloration
• 2. underhair – used for insulation by trapping a layer of air; dense, softer.
• 3 types of horns• 1. True horn – hollow w/a core made of bone arising from skull; can be found in both sexes; not normally shed (antelope, cattle, sheep)
• 2. Antlers – solid bone, covered w/velvet that sheds as it grows; only in males; shed after each breeding season. For several years each new pair is larger and more elaborate than year before (elk, moose, deer, caribou)
• 3. Rhinoceros horn – not attached to skull
• TEETH- adapted to food source.
• Deciduous teeth are replaced by permanent teeth (except molars)
• 4 kinds of teeth• 1. incisors – front teeth;
central and lateral (beavers- large incisors for gnawing and nipping)
• 2. canines – longer teeth; 2 top/2 bottom; used to catch, kill and tear prey (wolf)
• 3. premolar – next to canines; prominent in grazing animals
• 4. molar – back teeth; prominent in grazing animals
• Feeding specializations • Insectivores –feed mainly on insects; moles, anteaters, shrews and most bats
• Herbivores – feed on grasses and other vegetation.
• Browsers, gazers (cows) and gnawers (rodents and rabbits)
• Carnivores – feed mainly on herbivores
• Omnivores – feed on plant and animals (pigs, rats, primates)
• GLANDS• Eccrine glands secrete fluids
directly onto the skin. Apocrine glands secrete fluids into ducts which are then taken to the skin.
• sebaceous (oil) – lubricates and waterproofs skin and hair
• sudoriferous (sweat) – used to draw heat away from body; mixture of salt, urea, and water in which microorganisms convert to odorous products
• scent (musk) – found around face, feet, or anus; used for defense, species and sex recognition, and territorial behavior.
• mammary gland – present, but nonfunctional, in males; monotremes lack nipples, milk is discharged into depressions in belly where it is lapped up; milk contains water, carbohydrates, fat, protein, minerals, and antibodies.
• REPRODUCTION• Most have definite mating
season, usually winter or spring to coincide w/most favorable time for rearing young after birth. Female can copulate during its estrous cycle, during which she will ovulate (said to be in “estrus”). Ovulation ended by menstruation.
• Males can mate at anytime. Some off spring born alert/bright eyed (antelope born ready to run), others blind and naked (mice)
• Gestation is the period of time in which young develop inside uterus; the larger the animal, the longer the gestation and the fewer offspring.