Mammals 10 Characteristics of Class Mammalia 1 Body

Mammals

10 Characteristics of Class Mammalia 1. Body covered with hair 2. Skin contains sweat, scent, sebaceous, and mammary glands 3. 7 cervical (neck) vertebrae 4. Pelvic bones are fused 5. Movable eyelids 6. Endothermic (warm blooded)

Characteristics of Class Mammalia 7. 4 limbs for locomotion 8. 4 chambered heart 9. Eggs develop in a uterus w/ placental attachment 10. Milk from mammary glands to nourish young

Vocabulary for Class Mammalia Sebaceous: A type of mammalian epidermal gland that produces a fatty substance used for water proofing Uterus: A hollow muscular organ in female mammals in which the fertilized egg becomes embedded and develops into an embryo and then a fetus; provides nourishment Placenta: The vascular structure, embryonic and maternal, through which the embryo and fetus are nourished while in the uterus Mammary Gland: The breast. In female mammals, the mammary glands produce and secrete milk to nourish developing young.

Vocabulary for Class Mammalia Gestation: The period in which offspring are carried in the uterus Vivipary: Reproduction in which eggs develop inside the female body

3 Main types of Mammals 1. Viviparous/Placental 2. Marsupials 3. Monotremes

Viviparous/Placental Mammals • Includes most mammals • Examples: rodents, whales, elephants, dogs, cats, bats, and humans

Viviparous/Placental Mammals • Gestation ranges: The tendency is that the smaller animals have shorter gestation periods and vice versa Examples: • Mice = 21 days Cats & dogs = 60 days Humans = 9 months Elephants = 22 months There are exceptions: Whales carry their young for only 12 months

Viviparous/Placental Mammals • The number of young produced in a season depends on mortality rates. • Mice are prey, and can produce 17 litters of 4 to 9 babies = 153 babies a year

Viviparous/Placental Mammals • Most carnivores have only one litter with 3 to 5 babies per year • Large mammals such as elephants & horses have only one baby per year

Marsupial Mammals • Includes: Kangaroos, Koala bears, Opossum, & Wallabies • Are pouched, viviparous mammals that exhibit a second pattern of reproduction • Have a primitive placenta • The embryo is first enclosed by a shell membrane & floats free for several days in the uterine fluid

Marsupial Mammals • After “hatching” from the shell membrane, it “takes root” in the uterine wall & absorbs nutrients • Gestation is short, and give birth to tiny young that look like embryos • Early birth is followed by a long time of lactation & parental care. Opossum Babies in a Pouch

Marsupial Mammals: Kangaroos • Fertilization is followed by a 33 day gestation • After the joey (baby kangaroo) is born, it crawls to the pouch without help from the mother • It attaches to a nipple located in the pouch

Marsupial Mammals: Kangaroos • The mother can become pregnant during this time, but the new embryo will stop growing after the 100 cell stage. This period of rest is called embryonic diapause, and lasts for about 235 days while the first joey is growing in the pouch • When the first joey leaves the pouch, the embryo in the uterus will begin to grow again, be born, and crawl to the pouch • Mother kangaroos will have 3 young of different ages dependent on her for nourishment: a joey on foot, a joey in the pouch, and a diapause embryo in uterus

Monotreme Mammals • Include the duck-billed platypus and echidnas • Oviparous mammals (Egg layers), NO gestation • Has a thin leathery shell, 2 is laid in each clutch • Eggs are laid in a burrow nest and incubates for 12 days. • The young suck milk from the fur of the mother around the openings of the mammary glands

Ungulates • Ungulates: Animals with hooves (Deer, sheep, pigs, horses, giraffe, cows, antelope, camels, & moose) • • • Walk on their toes Many (not all) have antlers OR horns Accounts for the majority of the world’s herbivores

Ungulates • Horns: Hollow sheaths of keratinized epidermis arising from the skull – Are NOT shed & don’t branch – Grow continuously – Found in both sexes

Ungulates • Antlers: Composed of solid bone when mature – Develop under a covering of highly vascular soft skin called velvet – Except for caribou, ONLY males have antlers – Breeding season (Fall), the blood vessels constrict & the stag (male) removes the velvet by rubbing the antlers on trees – Antlers are shed after breeding season – Each year, antlers become bigger and more elaborate than the previous year

Flying Squirrels • Found in southeastern Canada, the eastern United States, and Mexico into Honduras and are as common as gray squirrels. • Are a nocturnal rodent species that glide silently through the woods while most of us are sleeping. • Loggers, rehabbers, and bird watchers are virtually the only people who experience the privilege of ever encountering them.

Flying Squirrels * The term "flying" is somewhat misleading, since flying squirrels are actually gliders, incapable of true flight. * Patagium: Is a furred membrane of skin, stretching from the fore leg to the hind leg. * Underneath the skin of the patagium lay long thin muscle groups that control some of its movement, and along the edge lies a group of intertwined muscle that serves to hold the skin flaps in various degrees of tautness as required during its glide. * When not gliding, another muscle group controls the now loose skin, keeping it out of the way when running, walking and sitting.

Flying Squirrels * Gliding is achieved by this animal by launching off the tops of trees and extending flaps of skin stretched from arms to legs. * They are highly maneuverable while in flight. * Steering is accomplished by adjusting tautness of the patagium, largely controlled by a the wrist bone. * The tail acts as a stabilizer in flight, much like the tail of a kite, and is used in "braking" prior to landing on a tree trunk.

Bats • A bat’s forelimbs are developed as wings, making them the only mammal naturally capable of true flight • Their wings are similar structurally to a human hand • Similar to flying squirrels, they also have a patagium membrane between the fingers that also stretches between the hand body.

Bats • There are 2 types: Mega bats and Micro bats • About 70% of bats are insectivores (insect eaters) and almost the rest are frugivores (fruit eaters).

• Bats are present throughout most of the world and perform vital ecological roles such as pollinating flowers and dispersing fruit seeds. • Many tropical plants depend entirely on bats for the distribution of their seeds.

Bats • Megabats (large): – – • Eat fruit, nectar, or pollen See very well Most do NOT echolocate Examples: Flying foxes, blossom bats, and more Microbats (small) – – Eat insects Do NOT see very well Use echolocation Examples: Little brown bat & big brown bat (common in GA) There are 16 different species in GA

Marine Mammals

Types of Marine Mammals Manatee Sea Lion Humpback Whale Sea Otter Bottlenosed Dolphin Polar Bear

2 Types of Whales: Baleen & Toothed Baleen Whales : – Includes Blue Whale, Gray Whale, Humpback Whale, Right Whale, & Minke Whale Toothed Whales: Obviously have teeth -- Includes Sperm Whale, Orca, & Dolphins

Baleen Whales • Generally larger than toothed • No Teeth • Have 2 blow holes Humpback • Have a “V” shaped blow • Filter feeders – using baleen

Baleen Whales 3 Types of Feeding Styles 1. Gulpers – Alternate between swimming (chasing food), & opening their mouth (Includes Blue Whales, Humpbacks, Minkes)

Gulpers • Some gulpers use bubble nets to fish • They work collaboratively, where one whale creates the bubble ring, & the rests of the pod comes in for the ambush

Baleen Whales 3 Types of Feeding Styles 2. Skimmers – Swim with their mouths open (Includes Right Whales & Bowhead Whales) 3. Benthic Feeders – Feed on the bottom (Gray Whales)

Baleen Whales – Baleen is a material similar to human fingernails – Baleen looks like the frayed teeth of a comb – Baleen’s inner edge has bristly to hair-like structures – When the whale gulps a mouthful of seawater, the baleen traps small crustaceans. The whale then closes it’s mouth, and spits out the excess water, leaving the small animals stuck to the baleen. The whale then uses it’s large tongue to collect them off the baleen and then swallows them.

Toothed Whales • Have teeth (duh) – Do NOT chew their food – They are used for grasping slippery fish • Eat Fish, seabirds, and marine mammals • Have ONE opening at the blowhole • Swim faster • Tend to be smaller • More social – live & hunt in pods (Family Groups)

Toothed Whales • Use echolocation or sonar to detect objects – They send whistles and clicks from their melon located on top of their head – They listen to the reflected echoes that bounce off objects & to the whale’s lower jaw. – The sounds allow the whale to create a mental picture of the object

Dolphins • Killer Whales (Orcas) are not whales, but a the largest dolphin!

Whale Behaviors Spy Hopping Breaching

Whale Behaviors • Tail Lobbing • Tail Sailing