What are the differences between donkey stallions, mares and geldings? Find out and understand more about their different behaviours.

The behaviour of all equines is influenced by the environment their ancestors evolved in, and the difference between the behaviour of donkeys and horses is largely down to the differences in these evolutionary environments.

Horses evolved living in harem or bachelor bands with stallions defending their band from other stallions. Each band has a home range that overlaps with other bands of horses. However, they do not defend these home ranges against other bands. In areas with sufficient water and vegetation, donkeys in the wild live in bands similar to horses, although they are more transient, often breaking up in the non-breeding season. In contrast, the ancestors of our domesticated donkeys who evolved in areas of sparse vegetation and limited water supply live more solitary lives where mares live with last year’s foal and stallions defend territories from other stallions in order to increase their chances of breeding with mares.

These differences in social behaviour result in domesticated donkeys exhibiting more territorial behaviour than horses. The donkeys’ territorial instinct is so strong that in many countries donkeys are used to guard herds of sheep and goats against dogs, foxes, coyotes and wolves. Unfortunately, this territorial nature means that it is not unheard of for donkeys to chase and attack small stock such as sheep, goats, poultry, cats, and dogs. However, not all donkeys display this behaviour and many donkeys live happily with these companions.


As stallions (also known as 'Jacks') mature their behaviour will generally become more challenging, especially if they live with other males or if there are females nearby. Young, entire male donkeys (known as 'colts') can be more difficult to handle as they mature sexually just as they would in the wild and as they reach two years of age they can start to cause problems for many owners. This is even more of a problem if the donkey has not been very well trained during these critical first two years of life.

The effect of hormones

Stallions can be very placid, friendly animals until for whatever reason their hormones kick in, which can cause a sudden change in behaviour. Donkey stallions and some geldings will fight very aggressively with other donkeys to the point of causing serious wounds on the neck and front legs of their opponents. Injuries can also occur to human handlers while stallions are fighting or trying to access female donkeys either accidently or as a result of direct aggression.

However, completely isolating stallions from other animals is unethical and can lead to further behaviour problems caused by stress and frustration.

Sexual activity

The young donkey stallion has the potential to mate with either his mother or sisters from around one year old, which can lead to unwanted foals or birth defects caused by inbreeding. In domestication older stallions will attempt to breed with their own female relatives if not kept separate, again leading to problems with inbreeding. Stallions can, in some cases, also be aggressive to foals, especially if they are not their own offspring or if they have been separated from the mare and foal for a length of time.


Geldings tend to be more predictable in their behaviour, but this does depend on how old they were when castrated. If a two year old donkey stallion has learned its own strength, then even after castration their difficult behaviour may remain. In time they may be less susceptible to the effects of their own hormones but their learned behaviour may continue making them difficult to handle.

The benefits of castration

The Donkey Sanctuary recommends that colts are castrated between the ages of 6-18 months and preferably as young as possible within that range. However, surgery is best done in the colder months of the year to minimise the risk of flies carrying infection to any surgical wounds. The younger it is done the less traumatic it should be and the greater influence on behaviour the surgery will have.

Once castrated, individuals will take differing lengths of time to settle into normal gelding behaviour patterns. This can range from anything between three months and a year. To avoid unwanted breeding it is advisable to keep older castrated males separate from mares for at least two months.

Although their behaviour with people is generally more predictable and calmer than stallions, it should be noted that even after castration, donkey geldings can be more sexually active than horse geldings and in some cases they will try to mate with mares and may fight with other males just as a stallion will do. The older they are when castrated the greater the likelihood that geldings may continue to act territorially and may chase livestock. This quite common stallion-like behaviour in geldings, can lead to people believing a donkey gelding is a rig. The term ‘rig’ describes a male donkey or horse that has been castrated but some reproductive tissue remains in place, causing stallion-like behaviours. Blood tests taken by a vet can reveal if this is really the case.

There are exceptions, but donkey stallions generally do not make good pets, and no one should keep a stallion unless they have the facilities and knowledge to do so. If you want a donkey for a pet, drive or just to take for walks then a gelding or mare would be more suitable than a stallion.

Despite their size, miniature donkey stallions can be just as difficult to handle and are potentially as dangerous as standard size donkeys. Therefore miniature stallions should be treated and handled in the same way and with the same respect as other stallions and are best gelded if not being kept for breeding.

It is better for the male donkey to experience the minor discomfort of surgical castration than to spend a life in an unsuitable environment with inadequate handling and to be frustrated and stressed by limited social contact with other donkeys. Castration also reduces the potential dangers to handlers and children from unpredictable stallion behaviour. Often colts may be bought at six months of age by unsuspecting owners, as they appear calm and easy to handle and sellers may advise they don’t need to be castrated. As the animal matures their behaviour often changes and then the owner has the expense of castrating the donkey.

Entire male mules are notoriously difficult and dangerous to handle, and they can be very determined to gain access to females and may attack other equines during times of frustration or when in close proximity to mares. However, when kept as geldings, male mules are much easier to handle and seem less stressed. Due to their parents' different numbers of chromosomes male mules are considered sterile and as such they have no reproductive potential. For these reasons it is always advisable to castrate male mules, and where practical to do it as young as possible.

Female donkeys

Female donkeys (also known as 'Jennies') are generally less territorial than males but again there are always exceptions to the rule. Male donkeys tend to use their front ends to defend themselves, while mares prefer to turn and kick out with their hind legs. Mares have their own set of behaviour issues generally related to changing hormone levels during their oestrus cycle. Mares generally come into season every 18-24 days depending on the individual. During the cycle they may have days when their behaviour is particularly difficult and days when their behaviour is normal or even very friendly. Each mare is different in her behaviour with some mares showing no signs of being 'in season' and their behaviour will remain consistent throughout their cycle.

Mares require patient, sympathetic handling during these hormonal fluctuations and to help predict these changes, owners with mares who show monthly fluctuations in behaviour are advised to keep a daily diary of their mare’s behaviour for at least three months in order to confirm their normal cycle. This will allow the owner to plan activities such as farrier or vet visits avoiding the most likely difficult days. Medical conditions affecting the female reproductive organs can also lead to difficult behaviour in female donkeys and a vet should always be consulted if such complications are suspected.

General advice

As a general rule, if you are going to keep donkeys for pleasure, it is advisable to choose geldings or mares and if you do buy young colts, they should be castrated as soon as possible.

Before deciding to breed from your donkey, please consider the number of donkeys taken into care by welfare organisations such as The Donkey Sanctuary. Having thought this through and ensured that, as far as is possible, the future of any foal is secure, and will have attributes superior to its parents, it is better to use the services of a stallion on the yard of a reputable donkey breeder than to keep an entire stallion yourself.

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Information for donkey owners