Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Beaver Teeth
Name: Nicky S.
Status: educator
Age: 20s
Location: N/A
Country: N/A
Date: Saturday, November 16, 2002

I have had many people ask me, while I was showing off a beaver skull, why they have yellow-orange incisors? I know beavers are rodents, and their incisors are constantly growing, and I have noticed this in all rodents also. But why is there a discoloration of the incisors (only) and not the other molars? Thanks!

The incisors are composed of two different materials, the outer, colored portion is harder, the whiter inner portion is softer. When the animals chew the softer material wears away faster than the colored, harder part so that the teeth are constantly sharpened as they wear and grow. I assume that the difference in color is simply due to the different composition.

J. Elliott

Click here to return to the Zoology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory