Aging Experience, Accuracy, and Precision
Matson’s experience level varies among different mammal species. We currently process approximately 100,000 – 115,000 teeth annually with a trend of steady increase. Last tabulated through December 2019, the count of teeth aged in our laboratory was 2,662,583, broken down by species as follows:
Species | Total Aged 1978 – 2019 | Oldest Age to Date | Origin |
Badger | 2,138 | 19 | Washington |
Bear, black | 786,008 | 35 | Idaho |
Bear, brown/grizzly | 70,754 | 39 | Alaska |
Beaver | – | 16 | N Territories |
Bison | 4,505 | 22 | N Territories |
Boar, wild | 56 | 11 | Spain |
Bobcat | 225,995 | 23 | New Mexico |
Caribou | 47,333 | 22 | Alaska, N Territories (tie) |
Coyote | 26,434 | 15 | Colorado |
Deer, black-tailed | 51,133 | 22 | Oregon |
Deer, mule | 132,953 | 20 | Washington |
Deer, roe | 1,897 | 15 | Belgium |
Deer, sika | 4,694 | 18 | Japan |
Deer, white-tailed | 327,045 | 22 | Louisiana |
Elk | 194,081 | 32 | Pennsylvania |
Deer, red | 3,349 | 20 | Spain |
Fisher | 32,055 | 10 | Minnesota |
Fox | 25,503 | – | – |
Fox, gray | – | 13 | California |
Fox, red | – | 16 | Sweden |
Fox, silver | – | 10 | Labrador |
Goat, mountain | 22,367 | 18 | British Columbia |
Lion, mountain | 75,662 | 22 | Montana |
Lynx | 18,929 | 18 | Switzerland |
Marten | 80,106 | 16 | Alaska |
Mink | 14,409 | 10 | France |
Moose | 167,335 | 22 | New Brunswick |
Muskox | 1,267 | 17 | N Territories |
Otter, river | 51,694 | 19 | Connecticut |
Otter, sea | 22,908 | 20 | Alaska |
Pronghorn | 18,594 | 17 | North Dakota |
Raccoon | 175,464 | 19 | Maryland |
Seal | 16,144 | 42 | Ontario |
Sheep, bighorn | 4,575 | 17 | British Columbia |
Skunk, striped | 9,742 | 12 | West Virginia |
Weasel/Stoat | 788 | 7 | New Zealand |
Wolf | 12,039 | 15 | N Territories |
Wolverine | 5,917 | 13 | N Territories |
Other species | 28,710 | – | – |
TOTAL | 2,662,583 |
To encourage continuing accuracy evaluation, Matson’s processes all teeth from known age animals without charge, providing the results can be shared in our periodic reports. Although we continue to collect accuracy and precision data, a thorough tabulation has not been made since 1998 and we expect new data to differ very little from those presented here. Known age material is not available to fully evaluate accuracy in most species, with exceptions being Alaska brown bear and Rocky Mountain elk.
Cementum aging accuracy can be expected to vary not only among different species and populations, but also among individuals in the same population. However, the evidence below indicates that most species should be aged with an accuracy of 70%, and 90% will be within 1 year of the correct age. For species that are difficult to analyze, 50% should be aged accurately and 85% will be within 1 year of the correct age.
Species with the most distinct cementum annuli occurring in the most regular pattern are expected to be the most accurately aged.
The following groupings reflect expected aging accuracy based on cementum characteristics.
High Accuracy (95%) Annuli very distinct, pattern very regular | Moderate (80-90%) Annuli and pattern somewhat distinct and regular | Low Accuracy (70-75%) Annuli indistinct, pattern irregular |
Badger | Bear* | Bison | Mountain lion | ||
Fisher | Black-tailed deer* | Bobcat* | Sea otter | ||
Fox | Caribou | Coyote | |||
Goat | Elk* | Marten | |||
Lynx | Mink | Moose | |||
Mule Deer* | Muskox | ||||
Pronghorn | Raccoon | ||||
River Otter | Sheep | ||||
Skunk | Weasel | ||||
White-tailed deer* | Wolf | ||||
Wolverine |
*Populations are variable, with some having cementum characteristics that yield high accuracy (e.g. Rocky Mountain elk, northern deer populations) and others that yield moderate accuracy (e.g. southern whitetail deer, southwestern mule deer, coastal elk). Supplementally fed animals have cementum annuli that are more complex and irregular than wild populations, which may lower the reliability of age analysis. For more information about supplemental feeding, see the Accuracy section of our Hunter & Outfitter page.
To end of 1996 | |||||
Species | Number | Aged Correctly | Error ± 1 year | Error > 1 year | Average Age |
Alaska brown bear | 77 | 52 | 22 | 3 | 4 |
Rocky Mountain elk | 52 | 51 | 1 | 0 | 4 |
Various 1975-95 | 477 | 331 | 103 | 24 | — |
To end of 1996 | 606 | 434 | 126 | 27 | — |
1997 | |||||
Species | Number | Aged Correctly | Error ± 1 year | Error > 1 year | Average Age |
Montana mule deer | 7 | 6 | 1 | 0 | 4 |
Montana elk | 13 | 12 | 1 | 0 | 5 |
Illinois white-tail | 9 | 9 | 0 | 0 | 1.7 |
Sea otter* | 3 | 0 | 3 | 0 | 9 |
*Three were analyzed “blind” from the same known-age sea otter. The known age was 9 years. The cementum ages for the 3 teeth were 8A(8-9), 8A(8-9), and 10A(9-10). |
1998 | |||||
Species | Number | Aged Correctly | Error ± 1 year | Error > 1 year | Average Age |
Montana elk | 4 | 4 | 0 | 0 | 10 |
Montana mule deer | 1 | 1 | 0 | 0 | 10 |
Michigan white-tail | 67 | 50 | 16 | 1 | 4 |
Minnesota white-tail | 10 | 9 | 1 | 0 | 4 |
Illinois white-tail | 6 | 6 | 0 | 0 | 2 |
To encourage continuing precision evaluation, Matson’s processes blind duplicates without charge, providing the results can be shared in our periodic reports. We will analyze a number of blind duplicates totaling up to 10% of the sample size, not to exceed 50 teeth (e.g. in a sample of 100 teeth, 10 blind duplicates will be processed free of charge). Although we continue to collect precision data, a thorough tabulation has not been made since 1998. Ongoing evaluations show precision continuing at levels observed in the past.
In the absence of known age teeth, precision measurements using blind pairs provide useful information because differing results for a pair are proof of error. Results of precision tests with blind duplicates follow (please note that accuracy for these species is expected to be moderate or low because of cementum characteristics).
Year | Species | Number | Aged Correctly | Error ± 1 year | Error > 1 year |
1991-95 | Various | 414 | 196 | 149 | 67 |
1995-96 | Mountain lion | 72 | 37 | 25 | 10 |
1996 | Mountain lion | 6 | 6 | 0 | 0 |
1996 | Wolf | 32 | 21 | 10 | 1 |
1996 | Caribou | 14 | 7 | 6 | 1 |
1997 | Black bear | 4 | 4 | 0 | 0 |
1997 | Moose | 11 | 7 | 2 | 2 |
1997 | Mountain lion | 13 | 7 | 3 | 3 |
1998 | Marten PM1 | 95 | 64 | 25 | 6 |
1998 | Moose | 51 | 36 | 8 | 6 |
1998 | Grizzly bear | 24 | 20 | 2 | 2 |
1998 | White-tailed deer | 18 | 12 | 4 | 2 |
1998 | Wolf | 6 | 5 | 1 | 0 |
1998 | Caribou | 7 | 6 | 1 | 0 |
All | — | 767 | 428 | 236 | 100 |