Mastodon Fossils-Rare in Colorado-Donated to Denver
Museum of Nature & Science
DENVER-October 1, 2009-Two young friends exploring a creek bed
in Ken Caryl Ranch after a heavy rain over the summer inadvertently
made a significant scientific discovery that informs the
understanding of Colorado's prehistoric past. Jake Carstensen
and Tyler Kellett, both 13, stumbled across a rare mastodon
mandible and tusk which could be 50,000 to 150,000 years old.
It is the best example of a mastodon ever found in Colorado, and
only the third discovery on record in the state. Both the mandible
and the tusk have been donated to the Denver Museum of Nature &
Science by the Ken Caryl Ranch Master Association, the owner of the
land where the discovery was made.
Carstensen and Kellett first discovered the mastodon mandible on
June 1, 2009, while exploring a stream and pool of water after a
period of heavy rain. The boys could tell right away they had found
the jaw of some large animal because it contained a huge tooth.
They brought their discovery home to determine what they had found.
After quizzing Tyler Kellett's father, Don, a wildlife biologist,
and ruling out every suggestion he made, the boys turned to the
internet to find some answers. They quickly realized they had
discovered the mandible of an American mastodon, a prehistoric
relative of the elephant that went extinct approximately 13,000
years ago. The boys contacted Dr. Steve Holen, curator of
archaeology at the Denver Museum of Nature & Science, who
confirmed their conclusion.
Holen was immediately interested in the discovery because unlike
mammoths, mastodon fossils are extremely rare in Colorado. With the
help of Dr. Greg McDonald, a senior curator of natural history with
the National Park Service and a Museum research associate, Holen
learned that there were only two other instances of mastodon
discoveries in Colorado on record-a tooth fragment was found
northeast of Pueblo in 1875, and a full molar was found in Golden
sometime prior to 1924 and donated to the Museum, which was known
then as the Colorado Museum of Natural History.
Holen returned to the area of the discovery with Carstensen and
Kellett to do some additional exploration in early August, when
they found the mastodon's tusk intact in a stream bank, submerged
in water. With the blessing of the Ken Caryl Ranch Master
Association, plans were made to temporarily divert the stream to
excavate the tusk and determine whether any other parts of the
mastodon skull were present.
The recovery of the tusk took two days to complete. On Saturday,
September 19, Holen, along with Carstensen, Tyler and Don Kellett,
and several other volunteers, began pumping water away from the
stream bed around the tusk. The group returned on Sunday, September
20, once the water was diverted, and began the challenging, messy
task of excavating the tusk. After digging carefully for several
hours, the five-foot segment of tusk was unearthed, wrapped
carefully in paper towels and plaster, and removed from the stream
bed. No other signs of the mastodon's skull were found during the
At the Museum, volunteers cleaned the mandible and applied a
preservative to prepare it for storage. The tusk is more fragile
and will remain in its plaster jacket for several more weeks until
it dries out, then it will undergo similar treatment. The
Museum has not yet determined whether the fossils will go on public
display. With the completion of the donation, the mandible and tusk
will be held in perpetuity as a part of Museum's permanent
collection of 1.4 million objects.