How Long Is a Guinea Pig’s Estrus Cycle — and What Are the Signs?
📝 Summary
Female guinea pigs cycle every 15–16 days for about 16–18 hours, mostly 5 PM to 5 AM; males have no fixed cycle and react to a female in heat. Signs include dropped appetite, urine-marking everywhere, mounting, cooing, and irritability. Year-round breeders can only be stopped by spaying, which is risky, so manage by learning the pattern.
1 Guinea Pig Estrus: Cycle and Symptoms
1. The guinea pig estrus cycle
1. Females cycle regularly, about every 15–16 days, each lasting 16–18 hours, mostly from 5 PM to 5 AM.
2. Males have no clear cycle — they are stimulated into heat. When a female is in heat, the male smells her pheromones and reacts; once she is done, he stops.
2. Symptoms of estrus
1. Appetite drops; long heat leads to weight loss, dull coat, and weaker immunity.
2. Both sexes urine-mark everywhere, even if litter-trained, to spread scent and attract mates.
3. Males circle females or other males, mount frequently, lower the head and ‘coo,’ and the testes enlarge.
4. Females get irritable, may mount males, and raise the rump for a male in heat.
3. How to stop estrus
Guinea pigs breed year-round; only spaying stops it, but the risk and cost are high, so it is not common. You cannot stop it by intervention — learn the pattern, avoid provoking them during heat, and feed nutritious, easily digested food.
Heat affects them less than cats or dogs, but long heat still hurts diet, mood, and growth; care for them well, or breed once or twice if you plan to.
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