Here's why:
* Irritant: Onions contain sulfur compounds that can irritate the mucous membranes in their eyes and nose.
* Tears: The irritation can cause them to tear up, leading to them closing their eyes.
* Avoidance: Guine pigs naturally avoid strong smells and will likely try to move away from the onion if they can.
It's important to note that:
* Onions are toxic to guinea pigs and should never be given to them to eat.
* Keep onions away from your guinea pig's living space to avoid any potential issues.
If you notice your guinea pig showing signs of irritation from onions, it's best to remove the source of the odor and ensure they have access to fresh air. If the irritation persists, contact your veterinarian for advice.