Why Echidnas Are Evolutionary Misfits

What makes echidnas and platypuses unique among mammals?

• They have scales

• They lay eggs

• They are cold-blooded

• They have gills

How do echidnas digest their food without a stomach?

• They have a very long esophagus

• They use a bony plate in their mouth to grind food

• They absorb nutrients directly through their skin

• They rely on bacteria in their intestines

What is a possible reason for the echidna's unusually long lifespan?

• They have a very high body temperature

• They have a low basal metabolic rate

• They eat a special diet of rare plants

• They are very large animals

Where does a female echidna lay her soft-shelled egg after it has grown inside her?

• In a nest made of leaves

• In a burrow underground

• In a special pouch on her belly

• In the water