Possible causes include:
* Dental problems: Overgrown teeth can prevent guinea pigs from eating properly, leading to weight loss and even starvation.
* Gastrointestinal issues: Parasites, infections, or even changes in diet can cause digestive problems, leading to weight loss and a loss of appetite.
* Stress: Extreme stress can lead to hair loss and even weight loss.
* Illness: A variety of illnesses, such as respiratory infections, can cause weight loss and hair loss.
* Nutritional deficiencies: A lack of essential nutrients, particularly vitamin C, can also cause hair loss and weight loss.
* Skin conditions: Mites, fungal infections, and other skin conditions can lead to hair loss.
What to do:
1. See a vet immediately. This is essential to determine the cause of the problem and get the right treatment.
2. Observe your guinea pig closely. Pay attention to any other symptoms they are exhibiting, such as lethargy, lack of appetite, or changes in their droppings.
3. Provide fresh, clean water. Ensure your guinea pig has constant access to clean, fresh water.
4. Offer a nutritious diet. Make sure your guinea pig is eating a balanced diet of hay, pellets, and fresh vegetables.
Important Note: I am an AI and cannot provide medical advice. The information above is for general knowledge only and should not be considered a substitute for professional veterinary care. Always consult a qualified veterinarian for any health concerns your guinea pig may have.