A Novel Objective Method of Estimating the Age of Mandibles from African Elephants (Loxodonta africana Africana)

Abstract

The importance of assigning an accurate estimate of age and sex to elephant carcasses found in the wild has increased in recent years with the escalation in levels of poaching throughout Africa. Irregularities identified in current ageing techniques prompted the development of a new method to describe molar progression throughout life. Elephant mandibles (n = 323) were studied and a point near the distal dental alveolus was identified as being most useful in ranking each jaw according to molar progression. These ‘Age Reference Lines’ were then associated with an age scale based on previous studies and Zimbabwean mandibles of known age. The new ranking produced a single age scale that proved useful for both male and female mandibles up to the maximum lifespan age of 70–75 years. Methods to aid in molar identification and the sexing of found jaws were also identified.

The skeleton of mammoth Mammuthus trogontherii cf. chosaricus Dubrovo, 1966 from terminal Middle Pleistocene of the Lower Volga region (Russia)

“…This stage pertains to XXVIII-XXIX groups of the African elephants by Laws (1966), and corresponds to 55 to 57± 4 years (based on Jachmann, 1988) or to the revised 57-62 years (based on Lee et al, 2012). This age, in Stansfield (2015). In our case the distance of 10 cm from the "age reference point" to the "age reference line" falls on the edge of the last plate of m3.…”

Mammuthus meridionalis (Nesti, 1825) from Apollonia-1 (Mygdonia Basin, Northern Greece) and its importance within the Early Pleistocene mammoth evolution in Europe

“…Missing values in PCA were treated by applying Iterative Imputation. Age at death was estimated using the dental-wear-based age criteria for the extant African savannah elephant Loxodonta africana provided by Laws (1966), and revised by Stansfield (2015) and Haynes (2017). Garutt et al 1990(see also Reich et al 2007and Lister 2017.…”

“…4) falls within Laws' group XXV, which corresponds to the average age of 49 in African Equivalent Years (AEY). Recent revisions on Laws' age assignments propose that this age group corresponds to an upper limit of 50 AEY with 70+ longevity for the African elephant (Stansfield 2015;Haynes 2017). Mammuthus meridionalis had a significantly larger body size than extant African elephants, and due to the general positive scaling of longevity to body size across mammals, also probably had a longer total lifespan (Eisenberg 1990;Maiorana 1990); therefore, a slightly older true age is expected for APL-716.…”

Kısa (Chihuahua köpek) ve Uzun (Asya fili) Ömürlü Hayvanlarda Artan Yaş İle Birlikte Telomerik Yıpranma

“…Unfortunately, age determination is difficult for most species, especially on living animals. Some methods involve using age-specific characteristics like tooth eruption and dental wear [1,2] , skeletal morphology [1,3] , body morphometrics [4] and bone ossification [5] , although most of these are applicable only after death. In addition, radiocarbon dating and aspartic acid racemization can serve as a tool for age estimation [6,7] , but again, not for living animals.…”