Unusually Aggressive Guinea Pig?

[HerePigTherePig]

One of my guinea pigs passed away recently, leaving her partner to her own devices. She didn’t go near where she had died, even after I cleaned out their cage. She didn’t seem very upset, as they had only known each other for a few months, but she did seem a bit shaken up.

Today I went to a local shelter to look at finding my little one a new partner, since she had lost hers. I found a two-year-old calico female, who seemed comfortable with people. She let me hold her, and she was calm during the ride home. I introduced them outside of their cage, which was newly cleaned, and when I saw that they got along well, playing and such, I let them wander around their cage.

My younger guinea pig seems most comfortable with an older female, because her first partner was a four-year-old female, and acted sort of as a mother figure to her. She followed around the calico, which went on without a hitch for a while, until I noticed that the calico was quite territorial. She would chase my younger one out of her hutch, and away from her own food. My younger one relegated herself to sitting in a corner, not daring to go out for fear of being chased away. When I tried to move the calico away with my hand so that the younger one could eat some of the food I put down, she jumped at it and started biting furiously. This led me to using their chew-log to push her away so that my young one could eat. They both calmed down enough to both eat at the same time, but I’ve never seen or heard of a guinea pig attacking not only other guineas, but people as well. I’m not sure where to go from here. Should I separate them? Get them some sort of divider?

 

[Piggies&buns]

character compatibility is the most important factor of whether two piggies will bond. Age is irrelevant. It seems you’ve brought this piggy home on spec and not dated at a centre (that’s fine, some centres don’t do dating), but it does mean there is a chance they won’t be compatible.

You say you introduced them outside of the cage, so they were in a neutral area. How long were they in the neutral area for?
If they are compatible and will bond and form a hierarchy, the complete process takes around two weeks. During this time you will see dominance.

Do you have two hay piles, two food bowls, two bottles, two hideys? If not, you will need to do this as you always need an item for each piggy so no hogging can occur.

Read the guides below which will help you decide you how things are between them and whether the bonding is going well or not. If it is going well (don’t forget you will always see some dominance) then don’t separate them. If you separate, then they will need to start all over again with a neutral territory reintroduction and start their bonding process from the beginning. If it isn’t working and there are clear signs of failure, then yes you will need to separate them.

Sows: Behaviour and female health problems (including ovarian cysts)
Bonding and Interaction: Illustrated social behaviours and bonding dynamics
Dominance Behaviours In Guinea Pigs

 

[Wiebke]

One of my guinea pigs passed away recently, leaving her partner to her own devices. She didn’t go near where she had died, even after I cleaned out their cage. She didn’t seem very upset, as they had only known each other for a few months, but she did seem a bit shaken up.

Today I went to a local shelter to look at finding my little one a new partner, since she had lost hers. I found a two-year-old calico female, who seemed comfortable with people. She let me hold her, and she was calm during the ride home. I introduced them outside of their cage, which was newly cleaned, and when I saw that they got along well, playing and such, I let them wander around their cage.

My younger guinea pig seems most comfortable with an older female, because her first partner was a four-year-old female, and acted sort of as a mother figure to her. She followed around the calico, which went on without a hitch for a while, until I noticed that the calico was quite territorial. She would chase my younger one out of her hutch, and away from her own food. My younger one relegated herself to sitting in a corner, not daring to go out for fear of being chased away. When I tried to move the calico away with my hand so that the younger one could eat some of the food I put down, she jumped at it and started biting furiously. This led me to using their chew-log to push her away so that my young one could eat. They both calmed down enough to both eat at the same time, but I’ve never seen or heard of a guinea pig attacking not only other guineas, but people as well. I’m not sure where to go from here. Should I separate them? Get them some sort of divider?

Hi!

Sows are especially prone to fear-aggression. Especially people orientated single piggies will often have not the first idea how to handle other piggies, will feel very insecure and over-react because they haven't had the constant interaction with their kind and the crucial socialisation during the formative 'school weeks' between weaning and teenage when babies are often sold as singles.
With sows you face also the added issue that leadership can very much contested when neither top lady (even if they lead a group of one) is will to step down.

Unfortunately when you get a companion on spec, you always need to allow for a bonding to not work, give the newbie time to settle in their new home and ideally give the piggies time to get to know each other through the bars for some time before introducing.

When guinea pigs are very much on edge, they will instinctively defence bite. This is an instinctive reaction to any sudden movement. There is a good reason why we recommend to have oven gloves ready for bondings.
Understanding Prey Animal Instincts, Guinea Pig Whispering And Cuddling Tips
" Biting" And What You Can Do (Biting, Tweaking, Nibbling and Nipping)

Please take the time to read all our green guide links in this thread. They will give you the necessary background information which we cannot explain in two short sentences as it is quite a complex area.
Here is more information on fear aggression (there is also a chapter on it in the very comprehensive illustrated bonding guide with lots of pictures and videos) and the challenges you may be facing when trying to bond singles. You may find the background information helpful in understanding what has happened and where you want to go from there.

Guinea pigs are social animals, but they are every bit as complex as the other social species, humans, when it comes to who they get on and want to live with. Arranged marriages to a stranger face the same problems...

Moody guinea pigs: Depression, Bullying, Aggression, Stress, Fear and Antisocial Behaviour
Single Guinea Pigs - Challenges and Responsibilities

 

[HerePigTherePig]

One of my guinea pigs passed away recently, leaving her partner to her own devices. She didn’t go near where she had died, even after I cleaned out their cage. She didn’t seem very upset, as they had only known each other for a few months, but she did seem a bit shaken up.

Today I went to a local shelter to look at finding my little one a new partner, since she had lost hers. I found a two-year-old calico female, who seemed comfortable with people. She let me hold her, and she was calm during the ride home. I introduced them outside of their cage, which was newly cleaned, and when I saw that they got along well, playing and such, I let them wander around their cage.

My younger guinea pig seems most comfortable with an older female, because her first partner was a four-year-old female, and acted sort of as a mother figure to her. She followed around the calico, which went on without a hitch for a while, until I noticed that the calico was quite territorial. She would chase my younger one out of her hutch, and away from her own food. My younger one relegated herself to sitting in a corner, not daring to go out for fear of being chased away. When I tried to move the calico away with my hand so that the younger one could eat some of the food I put down, she jumped at it and started biting furiously. This led me to using their chew-log to push her away so that my young one could eat. They both calmed down enough to both eat at the same time, but I’ve never seen or heard of a guinea pig attacking not only other guineas, but people as well. I’m not sure where to go from here. Should I separate them? Get them some sort of divider?

Update: Things have calmed down since yesterday. The two haven’t been bothering each other, and when I woke up I realized they had slept in the same home together. I almost put in a divider for them, but they’ve been getting along well as of today. The younger one can eat however she pleases, and she won’t be bothered. I have noticed that the calico is still shaken up, though. I realized that I have rushed things, and her biting me and my friend was her way of telling us to stop pestering her. I left the two alone for the rest of the day, except to give them a plate of veggies. They both ate soundly. Today I shook their treat bag, and the younger one came over to the front to get one, but the calico did not. I left it by the entrance of her home, and eventually she took it.

At the shelter she was in, her papers stated that her previous owners were too busy to take care of her. She had a partner in the past, but I’m not sure of the circumstances that she was put in. I am going to let the two continue to get comfortable, and then let them have floor time together. The little one likes to follow around the calico, and they both sniff each other sometimes when they cross paths. I haven’t seen them get upset at one another today, but I’m keeping an eye out. They two have their own areas where they can eat separately, and sleep separately if they wish.