Pasture mating behaviour of donkeys (Equus asinus) at natural and induced oestrus.

The research article investigates the mating behaviour of donkeys in pasture during natural and induced cycles of reproduction to understand their sociosexual structure, pre-copulatory interactions among other aspects of their mating activity.

Mating Behaviour of Donkeys

• The study observed the behavior of two males donkeys (jacks), each with a group of 21 non-pregnant female donkeys (jennies), in natural and induced oestrus conditions. Oestrus refers to the period of sexual receptivity in female mammals, comparable to the “heat” phase.
• The donkeys exhibited efficient pasture breeding under both natural and induced oestrus, indicating their adaptability to both conditions.

Sociosexual Structure

• The donkeys appeared to have a territorial sociosexual structure, where each jack controlled a specific territory and the associated group of jennies during mating.
• This territorial behavior can have implications on the spreading of good traits among the donkey population in that area, as dominant jacks get to mate with multiple jennies.

Pre-Copulatory Interaction

• The interaction before copulation (pre-copulatory interaction) among donkeys was prolonged, which might be indicative of a complex mating ritual or a careful selection process.
• The study observed that the jennies also actively participated in initiating these pre-copulatory interactions.
• These observations could contribute to understanding the nuances in their mating behaviors, such as courtship rituals and strategies.

Mating Activity and Copulatory Sequence

• The mating activity of donkeys was observed to increase gradually up to two days before ovulation, suggesting that they are guided by the biological signals associated with the females’ reproduction cycle.
• The sequence of copulation was found to be similar to that of horses, which is an interesting discovery given their close evolutionary relationship.

Vocalization and Heterotypical Behaviour

• Vocalization by the jack was identified as a prominent behaviour initiating the pre-copulatory interaction. This vocalization may act as a signal for readiness to mate or to attract the jennies for courtship and could be an interesting area for deeper ethological investigation.
• The jennies exhibited frequent heterotypical behaviour, which refers to behaviors that deviate from the typical ones. The specifics of these behaviours were not described in the abstract but could include a range of behaviors from differences in the initiation of mating to disruptive behaviors during mating.