Causes of natal dispersal and emigration and their effects on harem formation in Misaki feral horses.

The research studies the behaviors that influence the organization of Misaki feral horse populations, specifically natal dispersal, emigration, and harem formation.

Study Overview

• The study was conducted from 1979 to 1994 on two herds of Misaki feral horses in Japan.
• The research mainly focuses on the behaviors of natal dispersal and emigration – the former refers to the movement of young horses away from their natal or birth group, while the latter refers to the movement away from the natal or birth area.
• The study explores the causes of these behaviors and their effects on harem formation, which is the establishment of a stable family group led by a dominant male.

Main Findings

• The study observes that all male horses which survive to age 4 years and females which survive to age 3 years leave their birth groups between the ages of one and three.
• It was found that natal dispersal predominantly occurs around the time of the birth of a sibling, suggesting sibling birth as a significant cause.
• The study also finds a correlation between the number of young male emigrants and the total number of young males in another herd—it was negatively correlated—while the number of young female emigrants was positively correlated with the total number of young females in the birth herd.
• All stallions that emigrated and survived to age 5 formed stable harem groups, suggesting a significant correlation between natal emigration and harem formation.
• Resident mares were also found to establish stable consort relationships with harem stallions, again highlighting a significant correlation between residence and the formation of stable consort relations.

Significance

• The research provides valuable insights into the factors influencing dispersal and emigration in Misaki feral horses, contributing to our understanding of their social dynamics and survival strategies.
• This study’s findings could be valuable for wild horse management and conservation efforts, as well as providing a comparative basis for understanding similar behaviors in other feral horse populations worldwide.