Your constitution and charisma scores both increase by 1. 

Cavies are only slightly longer lived than their quadrupedal, domesticated counterparts. While non-sentient guinea pigs live only to around a max of ten years of age, the common Neath-born Cavie's lifespan is doubled to an average of a twenty-year lifespan. 

Alignment of the guinea pig can vary based on location and social class. Most Cavies are neutral but outside influences often tilt the scales into one extreme or the other.

Cavies are small in stature, standing anywhere from two to three feet tall. 

Your base walking speed is 25 feet.

You can speak, read, and write in English, as well as speak Rodent. Rodent is vocalized as a series of squeaks, chirps, and whistles. 

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

As an action, you can perform a bite attack against your enemy. This attack counts as an unarmed strike and has the finesse trait, so you can use either your STR or DEX bonus for the purpose of determining the attack and damage bonuses. On a successful hit you deal 2d4 piercing damage plus any modifiers. On a critical success the wound is substantial enough to impose disadvantage on the next attack that creature takes. 

Your squat stature and adorable, fuzzy cheeks give you an unassuming visage. You gain proficiency in the persuasion skill and gain advantage on persuasion and deception checks to convince someone of your innocence. 

You gain the ability to burrow in soft terrain (dirt, grass, sand, etc.). Your burrowing speed is 20 feet. You must use your action in conjunction with your movement to burrow through hard rock, which is considered difficult terrain for this purpose.