Pleistocene Ice Ages and Mammal Mega-Fauna

Question 1

When was “Last Glacial Maximum” (LGM)?

Answer 1

• started 25 kyr and ended 11 kyr ago

Question 2

Mastodon Teeth vs. Mammoth Teeth

Answer 2

Mastodon: more jagged like (for browsing)

Mammoth: look a lot like modern elephant teeth (stacked for grazing)

Question 3

Ice Age Carnivores of North America

Answer 3

American Lion, and American cheetah, Sabertooth Cat, Dire Wolf, Short-Faced Bears

Question 4

La Brea Tar Pits

Answer 4

• California

- predators remains greatly outnumber number of prey remains

Question 5

Quartnernary (end-Pleistocene) Mega-Fauna Extinction

Answer 5

• affected only those above 44 Kg. (and only land mammals)
• affected all continents but at different times
• dated at about 11 kyr B.P. (end-Pleistocene) in North America

Question 6

Evidence Supporting Overkill Hypothesis

Answer 6

For: timing of extinctions occurred relative to the arrival of humans in North America

For: evidence of mega-fauna being hunted

For: mega-fauna tend to take longer to raise children making it easier for generations to go extinct

Question 7

Evidence Against Overkill Hypothesis

Answer 7

Against: Mega-fauna in Australia went extinct long before humans arrive

Against: Bison were hunted too, how are they still around today?

Against: extinctions happened in North America before Bearing Land Bridge

Question 8

What are corollaries to large body size in mammals and why might this make them susceptible to extinction?

Answer 8

• greater individual longevity
• longer pregnancies (like miserably long, poor them)
• longer time to reach sexual maturity
• birth fewer offspring
• not as many individual mega-fauna to keep up with hunting humans

Question 9

Wrangel Island Refugium

Answer 9

• place of the last mammoths (Pygmy Mammoths)

- died ~6 kyr after End-Pleistocene Megafauna Extinction