Human-controlled reproductive experience may contribute to incestuous behavior observed in reintroduced semi-feral stallions (Equuscaballus).

This research article investigates whether the human-controlled reproductive experience and periods of captivity may contribute to incestuous mating behaviors in released male Konik Polski horses.

Research Context and Methodology

• The study was based on the observation of reintroduced male Konik Polski horses. The behavior of these horses was tracked from their juvenile period up to their stage of being sexually active stallions. The focus was on those that were kept in controlled environments with direct human control on their reproduction and eventual released into semi-feral conditions, as opposed to those that were born and allowed to grow in the wild without human intervention.
• The primary data collected in this study includes reproductive records for 46 mares and their offspring. Detailed records of the parentage of these offspring were scrutinized to identify any instances of incestuous mating. Furthermore, they observed the stallion’s expulsion of their daughters from the herd and mating behaviors with them.

Findings of the Study

• The research found that the male horses that had been held in captivity (C) expelled fewer of their daughters from their herds and mated more with their daughters compared to those who had not experienced captivity (nC). To put this into figures, 33% of C stallions versus 18% of nC stallions failed to expel more daughters, and 28% of C stallions mated with them, versus just 11% of nC stallions.
• Escalating this issue was human-controlled reproductive activity, as those stallions that had been used for in-hand breeding expelled fewer daughters (60%) and mated with more of them (33%), when compared to the nHC stallions that were not used for human-controlled breeding.
• All the stallions used for human-controlled breeding engaged in incestuous breeding at least once.

Implications of the Findings

• The evidence from this research suggests that human intervention during the formative years might disrupt the development of inbreeding avoidance mechanisms in these animals.
• The research suggests that the standard practice of separating young stallions from their herds for breeding under controlled conditions might contribute towards their incestuous behavior when they are later reintroduced into natural conditions.
• The researchers proposed that the lack of interaction among stallions, which prevents them from recognizing herd members, might be another factor encouraging incestuous behavior.