Aging the individual

1. Broad age class: classify the animal’s age group category i.e. calf, juvenile, sub-adult and adult.
2. More accurately estimating the animal’s age in years by evaluating the animal’s molar development.

Here we present characteristics of the age categories for body and tusks, and then for skull and teeth. The focus is on broad age classes (as 1, above), with some guidelines on low-tech field assessment of age from teeth. The first section (body / tusks) is useful generally if you have encountered a whole, relatively fresh carcass, or are looking at a live animal. The second is more useful for skeletons, focussing on skull and teeth.

Body & Tusks

	Age estimate	Body		Tusks
		Size	Appearance	Appearance	Shape
Juvenile	New born	Below one meter at shoulder length.The shoulder is less than the length of a G3 or AK47 rifle.	Hairy, grey skin, smooth, with no wrinkles	None	Nil
	2 years		No hairy patches on body	Emerging. Less than 8 cm in length	Nil
	3-8 years	Shoulder height  is between 1 and 2 meters high (taller than a rifle, up to a height taller than a human).	Body is usually “funnel shaped” from side view	Tusks grow steadily in length. The base of male tusks begin expanding from age three.The circumference at the lip line exceeds that of the base at around age 4 years of age.The lip line and base circumferences for females remains the same.Also, tusks of males splay outwards, this appearance becoming more conspicuous in older males. The tusks of females do not splay .	Shape for male tusks  is visibly different from females starting from age 3 or 4 years. From tip to base of tusks, males have an attenuated shape while females have slender, uniform shape of tusk except at the tip where wearing changes the shape of tusk around the tip area only.
Sub-adult	9-17 years	Shoulder height is above 2 meters high.	Body is “box shaped” from size view
Adult	18-60 years		Body shape differs for males and females.   Males: shoulder height rise above rump and this sloped shape becomes more prominent with age; Females: shoulder and rump remains same height but back elongates and shows saddle back, become more prominent with age

 

Skull & Teeth

Why use bones? The skull and teeth of a carcass can tell you with reasonable accuracy the age and sex of an elephant (also see the page on sexing). Skulls of calves and juveniles differ from those of sub-adults and adults. At adult stage, the differences also begin emerging at amongst early, middle and late adulthood between males and females. The shape of the skull changes up to adulthood, with the mandibles extending and growing and the skull growing taller. It is the teeth of an elephant that provide the best age estimate of the animal. Elephants develop six molars in each quadrant of their jaws during their lifetime. Each erupts at a certain age and wears at a particular rate. However, in order to achieve this, one must measure the length and width of a molar in order to identify to correct molar number. See ‘downloads’ for exact tables by Jachmann on determining the age of an elephant from tooth measurements.

 

A complete (full) molar has no frontal or rear wear, and has at least 8 or more lamellae (tooth ridges). In the absence of calipers, measure the length and width of the molar using your index fingers. This helps to estimate the correct molar number to use in estimating the elephant’s age according to Jachmann’s (1988) chart. One should also examine the teeth to assess the extent of eruption and degree of wear, as well as determine whether there were any previous teeth lost by looking for the empty socket of the previous teeth.

The lip bone tells us that this is a male (tapered, thick). The teeth tell us that the animal is approximately 18-20 years old, as molar #4 is half eroded.	The last molar (M6), totally worn down and less than half remaining. The elephant here died of old age, unable to feed itself properly.	Female lip bone (very narrow and slight). M5

Characteristics

Skull and teeth characteristics for various age classes are summarised below.

	Age estimate	Skull		Teeth
		Structure	Unique features	Size range	Observations
Juvenile	New born	Very soft, easily broken	The cranium usually disappears when carcass is still fresh	Usually no teeth visible, embedded in the skull#	Covered by gums, usually seen embedded in the lower jaw
	2 years	Hardened;  cranium parts separate easily at recent stage	Separation lines visible over cranium	Molar 2 full (less than 7 cm length), molar 3 growing	Three teeth visible on upper and lower jaws
	3 years	Similar for both sexes	Lip bone on lower law begins to differ between males and females#	Molar 3 fully grown, maximum 14 cm length; molar 4 growing	Socket for molar 2 visible; alveoli for molar 4 forming
	5 years
	8 Years				1 or 2 lamellae for molar 4 showing
Sub-adult	9 years		Molar cavity at the back of lower jaw open/not sealed#	Molar 4 fully grown, maximum 17.5 cm length; molar 5 growing	Front edge of molar 4 worn out
	13 years				Molar 5 showing
	17 years				Molar 5 with about 2 lamellae showing
Adult	19 Years	Base of skull shows swelling outwards  (males)#; female skull stays linear.		Molars 5 half grown with about 4 lamellae; molar 4 half worn out.
	25 years		Molar cavity at the back of lower jaw completely sealed#	Molar 5 fully grown, maximum 22 cm length; Molar 6 showing but no lamellae	Alveoli for Molar 6 showing
	35 years	Base of skull inmales prominently swollen#.		Molar 6 half grown; molar 5 half worn out
	50 years			Molar 6 fully grown, maximum 31 cm length
	Over 60 years			Molar 6 half worn out#.

How to measure teeth

Jachmann’s guide (see bibliography and the Studying Elephants book) gives a detailed overview of tooth measurement. Here we focus on approximate measures for the field.

Sometimes there will be a single exposed tooth (with worn lamellae) which you can measure; however you may also measure the length of the exposed lamellae of all teeth as an approximate indication (ignoring the rounded, non-exposed parts of rear teeth) of the age class.

Most adult human’s index fingers are around 7 cm long (but measure yours!) and thus the approximate positions seen here may be used as approximations in the field.

Measurement	Age / class	Illustration
A single tooth as long as, or smaller than, your index finger is M1 or M2.	Juvenile(calf –0-2 years
If longer than a single finger, up to two index fingers that touch along a tooth indicate M3 (or M2+M3) (10-14cm)	Juvenile –3-8 years
If there is a gap between your two index fingers this indicates M4, or M4 + emerging M5.	Subadult –9-17
A tooth longer than three finger lengths (long gap between fingers) is indicative of M5 or M6.	Adult –18 +	[ARTWORK PENDING]