Guinea pigs can learn complex paths to food, and can accurately remember a learned path for months. Their strongest and overwhelming problem solving strategy is 'activity' While guinea pigs can jump small obstacles, they cannot climb, and are not particularly agile. They startle extremely easily, and will either freeze in place for long periods or run for cover with rapid, darting motions when they sense danger. Larger groups of startled guinea pigs will "stampede", running in haphazard directions as a means of confusing predators. When excited, guinea pigs may repeatedly perform little hops in the air (known as "popcorning"), a movement analogous to the ferret's war dance. They are also exceedingly good swimmers.
Unlike many rodents, guinea pigs do not participate in social grooming, though they regularly self-groom. A milky-white substance is secreted from their eyes and rubbed into the hair during the grooming process. Groups of boars will often chew each other's hair, but this is a method of establishing hierarchy within a group, rather than a social gesture. Dominance is also established through biting (especially of the ears), piloerection, aggressive noises, head thrusts, and leaping attacks. Non-sexual simulated mounting for dominance is also common among same-sex groups.
Guinea pigs have poor sight, but well-developed senses of hearing and smell. Vocalization is the primary means of communication between members of the species. Some of these sounds are:
Wheek - A loud noise, the name of which is onomatopoeic, also known as a Whistle. An expression of general excitement, it may occur in response to the presence of its owner or to feeding. It is sometimes used to find other guinea pigs if they are running. If a guinea pig is lost, it may wheek for assistance.
Bubbling or Purring - This sound is made when the guinea pig is enjoying itself, such as when being petted or held. They may also make this sound when grooming, crawling around to investigate a new place, or when given food.
Rumbling - This sound is normally related to dominance within a group, though it can also come as a response to comfort or contentment. While courting, a male usually purrs deeply, swaying and circling the female in a behavior called "rumblestrutting".
Chutting and Whining - These are sounds made in pursuit situations, by the pursuer and pursuee, respectively.
Chattering - This sound is made by rapidly gnashing the teeth, and is generally a sign of warning. Guinea pigs tend to raise their heads when making this sound.
Squealing or Shrieking - A high-pitched sound of discontent, in response to pain or danger.
Chirping - This less-common sound, likened to bird song, seems to be related to stress. Very rarely, the chirping will last for several minutes.