Guinea pig sows live in groups and need a strict hierarchy to keep order.
Dominance
Sorting out the dominance is therefore vitally important for guinea pigs of the same gender.
Typical dominance behaviours include rumbling while shifting the weight from one back leg to the other ("rumble-strutting" ), teeth chattering, head-butting and nipping (a carefully judged gesture of power that lets the recipient only feel the teeth but not harm it, with the under-sow protesting loudly/squeaking submission) and bullying practices like taking over the hut, food bowl, hay etc.
nswering defiant clucking noise), yawning, going chin to chin (pushing their heads up facing each other), chasing, nipping and little scuffles can result. It can look pretty rough to us humans. Don't separate until there are serious, bloody fights; the girls NEED to sort out their differences without our interference!
Bonding should always happen in a neutral place to prevent the newbies from being seen/feeling as invaders and hostilities/over-reaction happening as a result.
In most cases the leadership is usually decided within a matter of hours or a couple of days, but it usually takes several days to tpyically around 2 weeks during the dominance phase to fully establish and settle the new hierarchy until a balance has been struck between how much the dominant girl can push her companion and how far the under-sow allows herself to be pushed, as well as for the dominance to travel down the new hierarchy ladder from to top to bottom in a group. During this time, especially while dominance is still including a lot of chasing, nipping and chucking out, please have only log tunnels or other hideys with two exits in the cage and either sprinkle feed or use as many bowls as their are piggies.
The strongest dominance always comes from the sow ranked just above in the hierarchy. Once higher ranked sows in a group or pair have established that a new arrival is not a challenge for their leadership, they will stay aloof and similar will any under-sows keep out of a leadership dispute.
When sows are pretty evenly matched, there can be a dispute. Teeth chattering (with the other party chattering back or making answering defiant clucking noise), going chin to chin (pushing their heads up facing each other), yawning, chasing, nipping and little scuffles can result. It can look pretty rough to us humans. Don't separate until there are serious, bloody fights; the girls NEED to sort out their differences without our interference!
Please do not provide any hideys at all during the bonding on neutral ground and remove any hideys with two exits once transferred to a cleaned and neutralised cage in order to prevent the underpiggy being locked in. Feed any veg and pellets by sprinkling across the cage floor or in one bowl per piggy in portions that can be eaten in one go and be removed in the between meals (since hay shoul make over 80% of the food intake, constant access to pellets, which should only come to about 5-10% is no longer recommended). Space the bowls over a body length apart, so access can't be blocked. Have hay and water bottles in two different places to avoid food bullying.
After they have sorted out the terms of their relationship, your girls will hopefully become more relaxed and friendlier with another. If that is not the case, if bullying behaviours/weight loss or not gaining weight in youngsters are continuing, please have the bullied piggy vet checked for a potential underlying medical problem and if that has been excluded, evaluate the situation with a temporary separation as described in the Bonds in Trouble guide.
More information and illustrations of bonding and dominance as well as of typical bonding dynamics behaviours here: Bonding: Illustrated Dominance Behaviours And Dynamics
Only in rare cases will a girl attack others on introduction. If blood has been drawn, the sows should be separated. A bonding has failed if two sows cannot come to an agreement as to which of them comes top or if there is systematic and persistent bullying of the under-sow that is in resulting in weight-loss/no weight gain in sub-adults or depression/staying away as much as possible from the bullying piggy well beyond the normal dominance phase.
Bonds In Trouble
Sows in season
Girls come into season about every 15-17 days. Most of the time you wont notice it, but sometimes they can be very hormonal and dramatic. I have observed that this happens more often with adolescent girls, freshly bonded or introduced sows (whether that is to another sow or a neutered boar) or after an operation that has interfered with the estrus cycle.
A sow coming into season can be grumpy or temperamental for a few days (especially if she is the alpha sow).
Over the roughly one and a half day of her season, she will sniff bottoms, rumble, chase and mount her companion as if she were a male. Even when a neutered boar is present, they will often rather chase and mount their female companions or even the boar before she is ready for mating at the end of her season.
Her companion will either kick her off straight away or allow her to hump until she's fed up, all accompanied by lots of squeaking and often a fair bit of kerfuffle! However, things should stay well below the level where fights would threaten. The humped sow will make it clear when she's fed up.
Well bonded girls will often reaffirm their bond with exchanges of affection on the following day.
When Sows Experience A Strong Season (videos)
Coming into season can spark a reopening of the dominance dispute, especially when the under-sow is not happy with the way things are.
Ovarian cysts
If these disputes become constant and one of the sows is behaving aggressively or in season all the time, please have her vet checked for a ovarian cysts/hormonal problems. Symptoms like crusty nipples, balding sides in the front and back legs are indicators of hormonal problems.
Please be aware that many cysts don't produce any physical or behavioural symptoms! It is also worth keeping in mind that not all ovarian cysts are hormonal it is often the very small cysts when they get going that cause the aggressive behaviour. In fact, the majority of ovarian cysts, which are present in many older sows, do not present with any symptoms at all and often go unnoticed.
If you see bleeding from the anus (often in small drops or patches and often as a one-off event, please have our sow's reproductive system checked by a piggy savvy vet. It can be the first sign that something more serious is wrong with the womb or a cyst. Sows do NOT bleed when they are in season!
There are now increasingly hormone treatments (chorulon injections or hormone implants) available as an alternative to a full spaying operation if the cysts are hormone based (not all ovarian cysts are).
For non-hormonal cysts or very large cysts, spaying is still the preferred option.
For very frail and/or older sows with large cysts we recommend considering draining as a valid alternative to a spaying operation as it doesn't require full or any anaesthesia. The result is not permanent, but will last for a number of months and can be repeated at need.
Guinea Lynx :: Ovarian Tumors
Permanent fall-outs
In rare cases, a sow that has been happily living with her sister or a companion for years can suddenly and for no apparent reason decide that she will not tolerate her companion any longer. It can also happen after a medically necessary separation that the operated girl may not be accepted back, even if she has been kept next door and had interaction through the mesh/the bars.
You can try to reintroduce the girls on neutral ground, but if they don't get on - especially after blood has been drawn - you will have to keep them separated permanently. Sadly, once a guinea pig has decided that another piggy is no longer part of "us", it will rarely change its mind; this is especially so with sows!
Dominance
Sorting out the dominance is therefore vitally important for guinea pigs of the same gender.
Typical dominance behaviours include rumbling while shifting the weight from one back leg to the other ("rumble-strutting" ), teeth chattering, head-butting and nipping (a carefully judged gesture of power that lets the recipient only feel the teeth but not harm it, with the under-sow protesting loudly/squeaking submission) and bullying practices like taking over the hut, food bowl, hay etc.
nswering defiant clucking noise), yawning, going chin to chin (pushing their heads up facing each other), chasing, nipping and little scuffles can result. It can look pretty rough to us humans. Don't separate until there are serious, bloody fights; the girls NEED to sort out their differences without our interference!
Bonding should always happen in a neutral place to prevent the newbies from being seen/feeling as invaders and hostilities/over-reaction happening as a result.
In most cases the leadership is usually decided within a matter of hours or a couple of days, but it usually takes several days to tpyically around 2 weeks during the dominance phase to fully establish and settle the new hierarchy until a balance has been struck between how much the dominant girl can push her companion and how far the under-sow allows herself to be pushed, as well as for the dominance to travel down the new hierarchy ladder from to top to bottom in a group. During this time, especially while dominance is still including a lot of chasing, nipping and chucking out, please have only log tunnels or other hideys with two exits in the cage and either sprinkle feed or use as many bowls as their are piggies.
The strongest dominance always comes from the sow ranked just above in the hierarchy. Once higher ranked sows in a group or pair have established that a new arrival is not a challenge for their leadership, they will stay aloof and similar will any under-sows keep out of a leadership dispute.
When sows are pretty evenly matched, there can be a dispute. Teeth chattering (with the other party chattering back or making answering defiant clucking noise), going chin to chin (pushing their heads up facing each other), yawning, chasing, nipping and little scuffles can result. It can look pretty rough to us humans. Don't separate until there are serious, bloody fights; the girls NEED to sort out their differences without our interference!
Please do not provide any hideys at all during the bonding on neutral ground and remove any hideys with two exits once transferred to a cleaned and neutralised cage in order to prevent the underpiggy being locked in. Feed any veg and pellets by sprinkling across the cage floor or in one bowl per piggy in portions that can be eaten in one go and be removed in the between meals (since hay shoul make over 80% of the food intake, constant access to pellets, which should only come to about 5-10% is no longer recommended). Space the bowls over a body length apart, so access can't be blocked. Have hay and water bottles in two different places to avoid food bullying.
After they have sorted out the terms of their relationship, your girls will hopefully become more relaxed and friendlier with another. If that is not the case, if bullying behaviours/weight loss or not gaining weight in youngsters are continuing, please have the bullied piggy vet checked for a potential underlying medical problem and if that has been excluded, evaluate the situation with a temporary separation as described in the Bonds in Trouble guide.
More information and illustrations of bonding and dominance as well as of typical bonding dynamics behaviours here: Bonding: Illustrated Dominance Behaviours And Dynamics
Only in rare cases will a girl attack others on introduction. If blood has been drawn, the sows should be separated. A bonding has failed if two sows cannot come to an agreement as to which of them comes top or if there is systematic and persistent bullying of the under-sow that is in resulting in weight-loss/no weight gain in sub-adults or depression/staying away as much as possible from the bullying piggy well beyond the normal dominance phase.
Bonds In Trouble
Sows in season
Girls come into season about every 15-17 days. Most of the time you wont notice it, but sometimes they can be very hormonal and dramatic. I have observed that this happens more often with adolescent girls, freshly bonded or introduced sows (whether that is to another sow or a neutered boar) or after an operation that has interfered with the estrus cycle.
A sow coming into season can be grumpy or temperamental for a few days (especially if she is the alpha sow).
Over the roughly one and a half day of her season, she will sniff bottoms, rumble, chase and mount her companion as if she were a male. Even when a neutered boar is present, they will often rather chase and mount their female companions or even the boar before she is ready for mating at the end of her season.
Her companion will either kick her off straight away or allow her to hump until she's fed up, all accompanied by lots of squeaking and often a fair bit of kerfuffle! However, things should stay well below the level where fights would threaten. The humped sow will make it clear when she's fed up.
Well bonded girls will often reaffirm their bond with exchanges of affection on the following day.
When Sows Experience A Strong Season (videos)
Coming into season can spark a reopening of the dominance dispute, especially when the under-sow is not happy with the way things are.
Ovarian cysts
If these disputes become constant and one of the sows is behaving aggressively or in season all the time, please have her vet checked for a ovarian cysts/hormonal problems. Symptoms like crusty nipples, balding sides in the front and back legs are indicators of hormonal problems.
Please be aware that many cysts don't produce any physical or behavioural symptoms! It is also worth keeping in mind that not all ovarian cysts are hormonal it is often the very small cysts when they get going that cause the aggressive behaviour. In fact, the majority of ovarian cysts, which are present in many older sows, do not present with any symptoms at all and often go unnoticed.
If you see bleeding from the anus (often in small drops or patches and often as a one-off event, please have our sow's reproductive system checked by a piggy savvy vet. It can be the first sign that something more serious is wrong with the womb or a cyst. Sows do NOT bleed when they are in season!
There are now increasingly hormone treatments (chorulon injections or hormone implants) available as an alternative to a full spaying operation if the cysts are hormone based (not all ovarian cysts are).
For non-hormonal cysts or very large cysts, spaying is still the preferred option.
For very frail and/or older sows with large cysts we recommend considering draining as a valid alternative to a spaying operation as it doesn't require full or any anaesthesia. The result is not permanent, but will last for a number of months and can be repeated at need.
Guinea Lynx :: Ovarian Tumors
Permanent fall-outs
In rare cases, a sow that has been happily living with her sister or a companion for years can suddenly and for no apparent reason decide that she will not tolerate her companion any longer. It can also happen after a medically necessary separation that the operated girl may not be accepted back, even if she has been kept next door and had interaction through the mesh/the bars.
You can try to reintroduce the girls on neutral ground, but if they don't get on - especially after blood has been drawn - you will have to keep them separated permanently. Sadly, once a guinea pig has decided that another piggy is no longer part of "us", it will rarely change its mind; this is especially so with sows!
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