[Phylogeny, form and function of canine teeth in the horse].

The research paper studies the evolution, structure, and function of horse’s canine teeth from its prehistoric ancestors to the present day. The findings indicate that the change in lifestyle and diet of horses over time has had a significant impact on the form of these teeth, which have served various roles in self-defense and social hierarchy establishment among the species.

Eocene Horse Hyracotherium

• The research traces the evolution of horse’s canine teeth back to the Eocene era horse, Hyracotherium. This horse species had simple, pointed, short-rooted teeth suitable for leaf eating and using as a means of self-defense.
• Living in pairs, these horses had lesser social interactions, and their teeth did not play a significant role in establishing social dominance.

Miocene Era Changes

• In the Miocene era, the living conditions of the horse species Merychippus changed. As they adapted to a grass-eating lifestyle and moved to living in herds, the role of their canine teeth also evolved.
• The research suggests that these teeth might have been used for fights to establish social ranking within the herd. As a result, the form of the teeth changed from a crown shape to a knife-like shape.

Pliohippus to Present Day

• In Pliohippus, the predecessor of the modern horse, the canine teeth usually remained only in male horses. Since the Pliocene era, these teeth served significant roles during fights between stallions to establish dominance and ensure only the strongest horses were successful in reproduction, aiding in the preservation of the species.
• The contemporary form and construction of the horse’s canine teeth are examined in detail in relation to these historical and behavioral attributes.