Guinea pigs cannot burp. Or vomit. They have no gag reflex.
Guinea pig females (called sows) have a hymen which dissolves every time they are in heat.
Guinea pigs produce two kinds of faeces. One is just waste, the other kind they eat. They do this for nutritional reasons.
The oldest living guinea pig ever recorded was a Peruvian (longhaired) called Snowball, from Canada. 15 years. The usual lifespan is about 5-8 years.
The domestic guinea pig is descended from the wild Cuy (plural Cuyos) and is native to Peru, especially the Andes region, Ecudor and Colombia . They are larger and leaner and have 5 toes on the front paws, 4 on the hind paws, as opposed to the 4 toes on the front and 3 on the hind found in domestic piggies.
Having said the above, polydactylism, (having an extra toe) is quite common in domestic guinea pigs.
Some guinea pigs have been known to hear a phrase of music and be able to sing it back in exact time and pitch. It's a rare gift.
Guinea pigs first came to Britain in the 16th century. They were pets for the aristocracy. Elizabeth 1 was a notable guinea pig owner.
They are called guinea pigs because when America was "discovered" it was thought by some sailors to be Guyana.. However in French they are known as "Cochon D'Inde" (Indian pigs) because some thought that they had reached India when they arrived there. In Finland and Germany respectively, they are known as "Marsu" and "Meerschweinen" both of which translate into "sea pigs" because they came from across the ocean.
Guinea pigs make two kinds of purring noises one is when they are happy and relaxed , the other is more like a low pitched growl, often accompanied by rattling teeth. This is when they are territorial or angry. Boars often sway their hips, and make a rumbling noise to impress sows. This is called Rumblestrutting.
Baby guinea pigs are called pups, not piglets.
When they are happy, guinea pigs will perennial high In the air. This is known as popcorning. When they lie flat it is called pancaking.