Guinea Pig Behaviour
Guinea pigs are social creatures and in the wild they live in large communities with the dominant male at the centre with his 'harem' and their offspring, surrounded by a bachelor colony of lower ranking males. When the young males show signs of being sexually active they are chased out to the bachelor group by the dominant male. To prevent inbreeding, the young females venture to the outskirts of the community to find themselves a mate that has less chance of being directly related to them. Normally she would return to the centre of the colony to give birth surrounded by more experienced females. If she does remain with the male who impregnated her they form a new colony. This is why if breeders take a female out of a female colony pen to be mated, and return her to the girl's pen after she's been with the male too long, the pregnant female may argue with the sows she used to get on with because she's developed a dominant 'attitude problem'.
Because bachelor males live on the outskirts of the main colony, they have plenty of space to get away from one another and avoid aggression. The main battles are over the females that migrate towards the edge of the colony to avoid mating with closely related males. In captivity, even in the absence of a female or scent of one, mature males can be aggressive towards unfamiliar adult males, although they normally accept baby boars quite kindly.
Guinea pigs give birth to fully furred babies with their eyes wide open, capable of running around very soon after birth. If the male is with her when she gives birth he will mate her immediately afterwards. Two pregnancies so close to one another takes a great toll on the sow's body and is one of the reasons sows in the wild return to the main colony where there are plenty of other females to protect her, help her feed and protect her babies and distract the dominant boar so she has a chance to recover.
Guinea pig mothers recognise their babies by scent but it is not uncommon for youngsters to be fed by sows who are not their mother. Other females help to clean up the babies after the birth. As youngsters reach weaning age they seem to be harried by the older females around them. Guinea pig society is a relatively peaceful place so this seems to be the guinea pig way of toughening the youngsters up and preparing them for the wider world.
Guinea pigs cannot vomit and so they are naturally cautious about new foods. Guinea pigs learn from each other what is safe to eat. If that chap didn't die then it must be o.k.! Their natural diet is grass and other plant material and they spend a lot of their time eating. In the wild they create tunnels in the long grass where they can move around safe from predators. They like the security of tunnels, huts and mounds of hay to hide in in captivity too.
They are very vocal creatures and they combine these sounds with clear body language. Males tend to be aggressive towards strange males. Teeth chattering and bottom waggling with small tense steps are signs of aggression. Low purring and soft bottom waggling are signs that the boar has taken a fancy to a female in the vicinity - or is hopeful about his male companion! Females use their ample behinds to butt lower status guinea pigs out of the way. Having chosen a favoured sleeping area, a dominant female will use this technique to remove an existing incumbent, a technique known as 'hot bedding'.
The classic 'wheek, wheek, wheek' sound is a greeting and a sign of anticipation. Most guinea pigs learn to associate their owners presence with food very quickly!
Seagulls Guinea Pig page has excellent information about herd behaviour and guinea pig communication.