The document discusses the giant beaver species Castoroides, which lived from 3 million to 10,000 years ago and was much larger than modern beavers. There were two known species, one found in Florida and one in Canada and the US. Castoroides could grow up to 8 feet long and weigh 130-220 pounds, comparable to a black bear. While their fossils are commonly found in the Midwest, remains have also been discovered as far as Florida and Canada. Theories for their extinction include hunting by humans or ecological changes during the Pleistocene period. Native American tribes also had myths involving giant beavers.

1. CASTOROIDES
GIANT BEAVERS
(GIANT BEAVER (CASTOROIDES OHIOENSIS) SKELETON ON DISPLAY AT THE FIELD MUSEUM OF NATURAL HISTORY IN CHICAGO, ILLINOIS. TAKEN AUGUST 2006 BY C.
HORWITZ, )

2. TABLE OF CONTENTS
Introduction
Classification
Description of Beavers
Fossils
Closing
Resources

3. INTRODUCTION
Castoroides, pronounced CASS-tore-OY-deez
or giant beavers, appeared at the start of the
Late Pliocene-Modern (3 million-10,000 years
ago) period and the Late Pleistocene period.
(Greek for "of the beaver family");
Graph found at Subcommission on Quaternary Stratigraphy

4. CLASSIFICATIONS
Only two known species:
Castoroides leiseyorum- Located in Florida
Known for shorter back legs, 6 inch incisors & narrow tail
Castoroides Ohioensis- Located in Canada and United
States
Known difference is molar teeth and premolor from the
Castoroides leiseyorum.

5. Skeletal and fossil evidence clearly display large teeth for
chewing wood and powerful claws for digging. Their diet
consisted mostly of plants.
2
3
1
Prehistoric Planet Store, Picture 1,2,&3 (2012)

6. Some of the fossil remains of beavers from this period resemble the living beaver of
today. Todays beaver is clearly smaller than the Castorodes beaver. This Ice age giant
was known to reach over 8 feet in length, and weigh between 130-220 pounds, making
him the largest known beaver, compariable to todays black bear.
07 January 2009 by Henry Nicholls
Magazine issue 2690.
Compared to each other
t Pro
life Managemen
Photo from Wild
Todays beaver
07 January 2009 by Henry Nicholls
Magazine issue 2690.
Photo from Kansas Dept of W, Parks and Tourismildlife

7. FIRST FOSSIL REMAINS WERE FOUND IN 1837, LOCATED IN OHIO.
MIDWESTERN UNITED STATES TENDS TO BE THE CONCENTRATED LOCATION
FOR FOSSIL REMAINS, BUT RECORDED FOSSILS ARE FOUND AS FAR AS FLORIDA
TO CANADA
Map from google
map .com

8. EXTINCTION POSSIBILITIES
Mans hunting of the beaver, but there is no solid
evidence to show proof.
Ecological reconfiguring during the Pleistocene
period.
Castoroides perished 10,000 years ago.
Fossil dates show Castoides to be 1.4 million years
old to 130,000 years old.

9. MYTHS
Native Pocumtuck tribe had a giant spirit named
Hobomock who killed the beaver was cursed to sleep
for perpetually as a mountain side of the earth.
Native Mi’kmaq also had a very similar myth.
Cree people were also among the myth believers.

10. THE AMERICAN BEAVER IS STILL COMMON IN THE LAKE TAHOE AREA TODAY.
THIS THREE FOOT, PADDLE TAILED RODENT EATS BARK AND SMALL BRANCHES
AND STOCKPILE SUPPLIES FOR THE WINTER. AFTER MILLIONS OF YEARS IT STILL
LIVES IN BURROWS OR LODGES BUILT FROM FELLED TREES.
Matt Renda Sierra Sun
Photo from 2012 - Cooksey-Talbott
Gallery
Every trail guide.com

11. RESOURCES
Canadian Museum of Nature, Notebooks: Giant Beaver
Kurtén, B. and E. Anderson (1980). Pleistocene Mammals of North America. Columbia University Press. pp. 236–
237. ISBN 0-231-03733-3.
"Giant Beaver: Natural History Notebooks". Canadian Museum of Nature. 2011-05-02. Retrieved December 2011.
Paleobiology Database, Collection 20403 and 20400. Location Leisey's Shell Pits 1A and 3B, Hillsborough County,
Florida. Authorized and entered by Dr. John Alroy, on February 18, 1993 and Mark D. Uhen, Ph.D.
Harrington, C.R. (1996). "Yukon Beringia Interpretive Center – Giant Beaver". Archived from the original on
2007-09-14. Retrieved 2007-09-17.
Reynolds, P.S. (2002). "How big is a giant? The importance of methods in estimating body size of extinct
mammals". Journal of Mammalogy 83 (2): 321–332. DOI:10.1644/1545-1542(2002)083<0321:HBIAGT>2.0.CO;2.