A free-ranging, feral mare equus caballus affords similar maternal care to her genetic and adopted offspring.

The research investigates a rare case of a wild horse adopting a non-genetic offspring, and concludes that the adoptive mare provided similar care for both her biological and adoptive foals, except for a slight increase in the distance kept from her genetic offspring.

Maternal Care Study in Equus caballus

• The study observed a free-ranging, feral mare, which is a variant of the horse species, Equus caballus, over the early developmental stages of its own offspring (born in 1995) and an adopted one (born in 1996).
• It’s uncommon for equids, which include horses, donkeys, and zebras, to adopt non-genetic offspring, making this study significant.

Comparative Measures of Maternal Care

• Five factors were used to compare how the mare treated both foals: total time spent suckling, the mare’s aggression during suckling, the number of mare-terminated suckling events, the amount of physical contact, and the distance between the mare and foal.
• Most of these factors showed no observable variance between the genetic and adopted offspring, indicating that the mare provided nearly the same level of care to both foals.

Genetic Offspring Distancing

• Interestingly, the only significant difference found was that the mare kept a larger physical distance from her genetic offspring compared to the adopted one.
• The study did not provide an exact explanation for this, although it could be an interesting topic for further research.

Hypothesis for Adoption

• This study also attempted to provide possible reasons why the mare may have adopted a non-genetic foal.
• One reason suggested is the postpartum physiological state — the physical and hormonal changes that a mare goes through after giving birth — which may compel her to adopt another foal.
• However, more research is needed to confirm this hypothesis.