Here's why their births might appear to occur at night:
* They are nocturnal: Guinea pigs are more active at night, so you're more likely to notice a new litter in the morning.
* Quiet births: Guinea pig births are relatively quiet, so you might not notice them happening.
* Safety and security: Having babies at night might provide a sense of security and minimize the risk of predators.
Ultimately, the time of birth for guinea pigs is influenced by various factors, including individual variations and environmental cues.