Global Warming Led to Dwarfism in Mammals -- Twice

Nov. 2, 2013 — Mammal body size decreased significantly during at least two ancient global warming events. A new finding that suggests a similar outcome is possible in response to human-caused climate change, according to a University of Michigan paleontologist and his colleagues.

Researchers have known for years that mammals such as primates and the groups that include horses and deer became much smaller during a period of warming, called the Paleocene-Eocene Thermal Maximum (PETM), about 55 million years ago.

Now U-M paleontologist Philip Gingerich and his colleagues have found evidence that mammalian "dwarfing" also occurred during a separate, smaller global warming event that occurred about 2 million years after the PETM, around 53 million years ago.

Read on

World's Smallest Mammoth Discovered

The smallest dwarf mammoth, standing at under 4 feet (about 1 meter) at the shoulders, has been uncovered on the Greek island of Crete, researchers say.

These findings could help yield insights as to how giant animals can shrink to tiny sizes over evolutionary time, scientists added.

Dwarfism often happens to species of large animals when they get trapped on islands,including dinosaurs. Scientists think dwarfism helps giants survive within the limits imposed by islands.

Ancient Mediterranean dwarf elephants are especially extreme examples of island dwarfism. Over the course of less than 800,000 years — a short stint on an evolutionary scale — these dwarfs are thought to have descended from larger European elephants, weighing 100 times as much, which lived on mainland Europe.

Read on:  http://www.livescience.com/20178-dwarf-mammoth-fossils-smallest.html