Guinea pigs are accepting of other guinea pigs joining their herd. They don't care if the piggy has long hair, short hair, or crazy hair. Guinea pigs can accept humans into their herd as well.
I wondered why guinea pigs didn't have the prejudice other animals--like humans--seem to have. But I think I have an answer. Guinea pigs don't recognize themselves in a mirror. In fact, if you bring them close to a mirror they are unhappy and seem very confused by the new guinea pig they've never seen before.
Hi
Sight is a guinea pig's weakest sense; they identify much more by scent and hearing. But sight is the strongest human sense, so for a long time we have instinctively used self-recognition in a mirror as a touchstone of intelligence and self-recognition.
A change in view of other animals having very much a sense of self but with other more significant identifiers is currently making scientific research rethink their tenets.
Guinea pigs are group animals; they identify first and foremost by their group - even if it is a group of one. They have evolved in contact with other groups living relatively nearby and feeding together peacefully as a herd twice a day. A group is however territorial in their denning area. Territorial behaviours between cage neighbours or fallen out piggies are however often misinterpreted because most piggy owners are not aware of that aspect.
Other piggies are either part of 'us, the group' or not part of 'us'. Bonding works from 'maybe part of us' to either becoming part of 'us' or not becoming part of 'us', or 'we don't want you here' right from the word go (acceptance not happening). Bonding success is never a given and always comes down to personal dynamics and aspirations. You can never just stick two piggies together and expect them to get on.
The longer and the more I know my piggies after half a century and around 80 of them passing through my life in all kinds of formations the more complex their personalities and their social interactions become because of me picking up on the finer nuances. Guinea pigs are for me right up there with human people, just with a very different social structure and their own differing priorities.
The looks issue is a bit more complex. Guinea pigs have a good idea of how they look from grooming themselves but of course they cannot see their own faces.
A mirror is not just puzzling because it is showing a 'strange' piggy that in parts looks very familiar. Much more crucially for cavies, the strange piggy doesn't come with an identifying scent. In my own experience with mirrors and guinea pigs, the lack of scent and touch and the lack of appropriate interactive responses is what throws it for them much more than seeing another guinea pig where they don't expect one.
How a piggy reacts to seeing a new piggy in the mirror at first also depends on how much they are used to interaction with a different range of guinea pigs or not. A single piggy will be much more wary than one that is used to neighbours and new arrivals in the room and to interacting with them not just in their own group but through the bars as well. Piggies that have daily interaction with a larger range of piggies behave much more welcoming. My Ceri for instance went straight up and greeted herself with a nose bump and a lick of the mirror.
Guinea pigs are actually often initially and instinctively drawn to new guinea pigs that look similar to them and evoke a family connection in my own long term owner experience and after lots of bondings; some more than others. I found it interesting when any newly adopted rescue-born babies would usually choose the most similar looking adult in their group as their personal guardian and teacher through the 'school weeks' between weaning and teenage.
While some guinea pig breeds and coat patterns go back hundreds and likely thousands of years (considering that domesticated guinea pigs go back 3000-6000 years), most core groups consist of a breeding group of often closely related sows, so the family look wiring is still kicking and alive to a certain degree. It does however not necessarily come with automatic acceptance into a group.
Like other pet species, guinea pigs will however always recognise other domestic breeds as belonging to their species and as part of the general breeding pool whereas wild guinea pigs and domestic guinea pigs do no longer interbreed and show significant differences both in their behaviour, physiognomy (including brain size and how they use their brains) and biology - wild cavy species have a distinct breeding season over the summer half year with 3-4 litters while domesticated guinea pigs can breed nonstop.
I have written an extensive article series for Guinea Pig Magazine over the last year and the start of this year exploring various aspects of guinea pig social identity and their rather complex social life. You may find it interesting. The series runs from issue #63 - #70.
Home - Guinea Pig Magazine