Types of Mammals NB #161

2 Main Groups: Prototheria: monotremes Theria: marsupials & placentals

Monotremes Egg laying mammals ◦ Retain eggs in their bodies for an extended time 5 species: duck-billed platypus & 4 species of echidnas (spiny anteaters) Short-beaked echidnaduck-billed platypus

Monotremes “Monotreme”– means “single opening” ◦ They have a cloaca instead of an anus, urethra, & vagina Live in Australia & New Guinea No nipples- excrete milk through mammary glands in the skin ◦ Display parental care

Monotremes Lack teeth as adults (have molars as young) Spur in the ankle- produces powerful venom in the male platypus Bill on the head functions in electroreception Platypus video

Marsupials (metatherians) Young are carried in a pouch Includes kangaroos, koalas, oppossums, wombats, & the Tasmanian devil kangaroo Tasmanian devil koala

Marsupials Most live in Australia & New Guinea ◦ We have one here…. Do you know what it is? Young are born early and then climb into their mother’s pouch to fully develop * The placenta does not develop Kangaroo baby * Young are called “joeys”

Placental Mammals Give birth to live and developed young * Nourish young with a placenta (organ developed during pregnancy for gas exchange, waste elimination, & nutrient uptake) Includes elephants, manatees, anteaters, cattle, whales, badgers, dogs, & humans

Placental Mammals With the exception of the opossum, all mammals native to North America, Europe, Africa, and Asia are placental mammals (eutherians)

Placental Mammals Wide opening at the bottom of the pelvis for large, well-developed offspring

Placental Mammals Hippopotamus- large herbivores in sub- Saharan Africa ◦ Closely related to whales ◦ Spend most of their lives in water ◦ Very aggressive- one of the most dangerous animals in Africa (humans are their only predators)

Placental Mammals Elephant- largest land animal ◦ Large proposcis modified into a trunk (mostly used for grabbing items) ◦ Incisors grow into tusks used for digging and fighting

Placental Mammals Tigers- largest cat species & third largest land carnivore (behind polar bear & brown bear) ◦ Now highly endangered due to fur poaching

Placental Mammals Blue whale- largest animal to ever exist on Earth (98 feet long & 170 tonnes) ◦ Teeth modified into large plates called “baleen”– eat tiny krill ◦ Endangered due to whaling

Placental Mammals Manatees- also called sea cows ◦ Large aquatic herbivores  Known to wipe out plants from an entire area ◦ Slow moving- often killed by boats ◦ Sailors used to confuse manatees with mermaids

Placental Mammals Primates- lemurs, bush babies, monkeys, gibbons, gorillas, chimpanzees, & humans Opposable digits on the feet and/or hands Humans- adapted an upright posture, ability to use and manipulate tools, bipedal locomotion, & highly complex brains ◦ Homo sapiens- our scientific name!! (evolved as early as 195,000 years ago)