Lineal Discrimination of Horses and Mules. A Sympatric Case from Arauca, Colombia

Abstract

This is the first morphological comparative study between local horses and mules from Arauca, Colombia. It was realized to compare morphological traits between both species by analysing 15 adult mules (7 males and 8 females) and 150 adult horses (137 males and 13 females), with an age interval from 2 to 22 years. Data consisted of 24 different body quantitative traits which can explain the body conformation: thoracic circumference, body length (BL), thoracic depth and width, withers height (WH), sternum height, shoulders width, chest width, forelimb cannon perimeter and length, head length and width, skull length and width, face length and width, ear length and width, loin height, croup height (CrH), width and length, dock height (DoH), and hock height. Heart girth circumference, body length, withers height, croup height, and dock height were the most discriminative traits, showing statistical differences between species. The formula is X = (BL × 0.402) + (WH × 0.323) + (CrH × 0.352) + (DoH × 0.384). A value of X > 184.5 assigns with total certainty that a skeleton belongs to a horse, and if X < 174.0, it is a mule. The proposed formula has a 100% specificity but a 71.4% sensibility for mules and an 84.4% for horses into the rank of 174.0–184.5. Therefore, results demonstrate that some postcranial anatomical elements of Equus could give enough information for a bone differentiation between horses and mules, at least in animals from the Araucan region, but the main interest is that it reflects the possibility to differentiate morphometrically both species from bone remains when horses and mules were sympatric.

No Morphological Integration of Dorsal Profiles in the Araucanian Horse (Colombia)

“…A sample of Araucanian horses was studied. The Araucanian horse is a creole breed located in the Orinoquia flooded savannah of Arauca, NE Colombia, an area located between 06 • 02 40 and 07 • 06 13 north latitude and 69 • 25 54 and 72 • 22 23 west longitude [15][16][17]. It is a large, flooded ecosystem (around 15,000 km 2 ) with intensive dry and rainy seasons, where cattle are raised in an extensive way and farmers ("rancheros") ride horses for their work.…”

“…They are bred in a totally extensive way with a diet based on natural grasses [15,16]. The Araucanian horse presents a wide chromatic variety, from basic coats-grey, black, bay, and chestnut-to combined patterns-piebald, appaloosa, and its endurance is notable [15][16][17].…”

Basicranial Modular Organization. A Study in the Araucanian Horse of Colombia

“…The Araucanian horse constitutes an equine population typical of the ecosystem of the Araucanian plains in NE Colombia. Of great rusticity, it has hardly been studied in its ecological environment until recently, when investigations have been initiated aimed at its morphological description, functional study, and genetic management [13][14][15]. The Araucanian horse represents a cultural and genetic heritage adapted to the environment of the flooded savanna; therefore, a morphological study might reveal its evolutionary traits of adaptation to the environment.…”

Classification of an equine skull in the Science Museum of Coimbra, Portugal, by means of multivariate and qualitative analysis

“…Equids biodiversity has been characterized using morphological measurements (Zhu et al 2014;Salamanca-Carreño et al 2020). Living species of Equus can be differentiated by a number of morphological characters (Bennett 1980).…”