• High accuracy (95%) = Annuli very distinct, pattern very regular
  
• Moderate (80-90%) = Annuli and pattern somewhat distinct and regular
  
• Low (70-75%) = Annuli indistinct, pattern irregular
  
  

High accuracy	Moderate	Low
Badger	*Bear	Mountain lion
Fisher	.Bison	Sea otter
Fox	*Black-tailed deer
Goat	*Bobcat
Lynx	.Caribou
	.Coyote
	*Elk
	.Marten
	.Mink
	.Moose
	*Mule deer
	.Muskox
	.Pronghorn
	.Raccoon
	.River otter
	.Sheep
	.Skunk
	.Weasel
	*White-tailed deer
	.Wolf
	.Wolverine

*Populations are variable, some having cementum annulus characteristics expected to yield high accuracy (e.g. Rocky Mountain Elk, northern deer populations) and others to yield moderate accuracy (southern and game farm fed whitetail deer, southwestern mule deer, coastal elk).

Note: Supplementally fed animals have cementum annuli that are characteristically more complex and irregular than wild populations. These characteristics may lower the reliability of age analysis. See additional information in the Accuracy section of Private Hunter, Outfitter, Hunting Club, & Game Farm Clients.

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Precision

To encourage continuing precision evaluation, Matson's encourages biologists to send "blind" duplicates (paired teeth from the same animal processed without the pairs being identified until after aging). We will process a number of blind duplicates up to 10% of the total sample size, not to exceed 50 teeth. For example, in a sample of 100 teeth 10 blind duplicates would be processed without charge. The resulting precision will be shared on this site and in other publications of the lab. We continue to collect precision data but have not comprehensively tabuated them since 1998. Ongoing evaluations show precision continuing at levels ovserved 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. Clearly, however, results that agree for a pair are not proof of correctness. Results of precision tests with blind duplicates follow (note, from the groupings given above, that accuracy for these species is expected to be moderate or low because of cementum characteristics).

Years	Species	n	Agree	+-1	+-1+
1991-95	Various	414	196	149	67
1995-96	Mt lion	72	37	25	10
1996	Mt 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	Mt lion	13	7	3	3
1998	Marten PM1	95	64	25	6
1998	Moose	51	36	8	6
1998	Grizzly	24	20	2	2
1998	WT deer	18	12	4	2
1998	Wolf	6	5	1	0
1998	Caribou	7	6	1	0
All	-	767	428	236	100-

Precision of Matson’s Lab Age Analysis Technicians

Technicians with more than a year’s experience at our lab can have an opportunity to participate in our in-house training program for age analysis. Species technicians may age are: Black bear, brown bear, elk, whitetail deer, mule deer, raccoon, bobcat, fisher, and marten. Gary Matson checks 10% of all samples aged by technicians. See "Precision of Matson's Lab Age Analysis Technicians"

GENERAL CEMENTUM AGE ACCURACY/PRECISION STATEMENT

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 cited above indicates that most species should be aged with an accuracy of 70%, and 90% within 1 year of the correct age. For species with accuracy expected to be low because of indistinct annuli and/or irregular pattern of annulus deposition, 50% should be aged correctly and 85% within 1 year of the correct age.

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Photomicrographs:

From J-O Helldin; Swedish red fox; aged 3-10-04 as 16A (15-17)

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Matson’s Lab recently processed and analyzed a North Dakota pronghorn tooth that is the oldest aged in this laboratory. The age of 17 years eclipsed the prior record of 15 years set by an Oregon pronghorn tooth and equaled by one from New Mexico. Most pronghorn harvested are younger than 5 years (photo at left). The record tooth on the right has a thick cementum layer, and not all the annuli are visible in the photo. The first annulus indicates the age of 2 years, because the tooth erupts at the age of 1. The first annulus is formed during the second winter of life. There are 16 annuli in the record tooth.

From Jesse Kolar; North Dakota pronghorn; aged 4-7-05 as 17A (photo at right)

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