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Nearly 40% of mammal species are rodents, and they are found on every continent except Antarctica. Rodents include mice, rats, squirrels, chipmunks and beavers, among others.

Why do beavers build dams?

Environmentalists agree that beaver dams help the environment by creating wetlands but why are some landowners and farm owners getting riled up? How could these dams be hazardous to roads, bridges and levees?

Naked Mole Rats Survive Without Oxygen by Turning Into Plants

Naked mole rats perform a feat of metabolic magic, according to a new study. Learn more in this HowStuffWorks article. See more »

These Arctic Squirrels Repeat Puberty Every Year of Their Lives

How does hibernation affect the life cycle of the Arctic ground squirrel? This HowStuffWorks article looks at the impact on male puberty. See more »

5 Things You Didn't Know About Squirrels

They're cute, furry and pretty smart too. HowStuffWorks Now tells you more about the humble squirrel. See more »

Madagascar's Most Famous Species Is Near Extinction

Why are lemurs on Madagascar at risk of extinction? Learn more about endangered lemurs in this HowStuffWorks Now article. See more »

Rats Are Ticklish Just Like Humans, New Study Shows

Are rats ticklish? What can that tell us about the human brain? Learn more about a new study on ticklish rats in this HowStuffWorks Now article. See more »

Goodbye, Melomys: Climate Change Claims Its First Mammal Species

The Bramble Cay melomys is the first mammal extinct due to climate change. Learn more about the Australian melomys in this HowStuffWorks Now article. See more »

To Save the Galapagos Islands, We May Need to Modify Rat DNA

How could altering rat DNA reduce the population on the Galapagos Islands? Learn more about GMO rats in this HowStuffWorks Now article. See more »

Prairie Dogs Savagely Kill Squirrels to Eliminate the Competition

Prairie dogs kill ground squirrels to eliminate the competition and also gain breeding advantages. Learn more in this HowStuffWorks Now article. See more »

'Off Switch' for Appetite Accidentally Discovered in Brain Enzyme

Scientists have discovered a brain cell that appears to turn off a mouse's appetite. Learn more in this HowStuffWorks Now article. See more »

Bushy-Tailed Woodrat has a habit of stealing shiny objects. Learn more about this creature at HowStuffWorks. See more »