That number was an estimate rather than a guaranteed final total.
Not every pregnancy necessarily results in exactly four babies, and the actual number of surviving offspring can vary. Modern veterinary information from the MSD Veterinary Manual gives an average guinea pig litter size of around two to four pups, with pregnancy lasting approximately 59 to 72 days.
That makes the park's estimate of around 400 babies understandable: if roughly 100 females were pregnant and each produced around four pups, the total could approach that number.
In other words, the mathematics behind the expected population boom was surprisingly straightforward.
The difficult part was figuring out how one little male had managed to create the situation in the first place.
Guinea Pigs Can Multiply Surprisingly Quickly
Although Randy's story sounds almost unbelievable, guinea pigs are capable of reproducing relatively quickly.
The RSPCA notes that guinea pig pregnancies typically last around nine to ten weeks. It also warns that young guinea pigs can reach reproductive age surprisingly early, meaning that an accidental male-and-female pairing can lead to a rapidly expanding population.
The MSD Veterinary Manual similarly lists an average gestation period of approximately 68 days and an average litter size of two to four offspring.
This reproductive ability is one reason why correctly identifying the sex of guinea pigs is so important.
The RSPCA specifically advises owners to make sure they know whether their animals are male or female and to check the sex of young guinea pigs as well. An unneutered male and female kept together can quickly result in an unexpected litter.
At Hatton Country World, however, the park had already taken the basic precaution of separating the sexes.
The problem was that Randy apparently found a way around that system.
How Did Randy Get Inside?
That remains one of the more entertaining mysteries surrounding the story.
Staff could not say with certainty whether Randy escaped on his own or whether he was accidentally placed in the wrong enclosure.
The park manager suggested that a child might have handled Randy and accidentally returned him to the female enclosure. Another possibility was that Randy had simply escaped and made his own way into the neighboring area.
There was no confirmed explanation for precisely how the escape happened.
What staff did know was that Randy had apparently remained in the female enclosure for long enough to mate with a very large number of females.
And because guinea pig pregnancies do not become immediately obvious, it took time for anyone to realize that something had gone wrong.
By the time the females' pregnancies were noticed, the mystery had already developed into a full-scale population problem.
The Evidence Was Right Under Their Noses
Perhaps the funniest detail of the story was that Randy himself was apparently the evidence.
Staff eventually discovered him sleeping in a pile of straw.
Instead of looking like a hardened escape artist, he apparently looked exhausted.
The fact that he was thinner than expected also attracted attention.
Once the staff identified him as male and realized where he had been spending his time, the strange pregnancies suddenly made sense.
There was no mysterious illness.
There was no unexplained biological phenomenon.
There was simply one male guinea pig who had somehow gained access to a very large group of females.
The discovery transformed what had initially been a puzzling situation into an extraordinary animal story.