If Fluffy has blessed you with a litter of kittens, you may be surprised to see a variety of colors and markings among her babies. If that's the case, it's a good chance that she's had the affection of more than one boyfriend. In the cat world, that's normal.
Polyestrous: Multiple Heat Cycles
Your kitty has a remarkable reproductive system. Cats' heat cycles are tied to day length; in the northern hemisphere when the days begin to lengthen, female cats will begin to cycle, coming into heat about every two weeks. This will last through the spring and summer and tends to stop in the winter months. If left to breed naturally, your feline friend would likely have two or three litters of kittens per year. If allowed to mate through her prime breeding years -- up to about age 8 -- she could have anywhere from 50 to 150 offspring.
Superfecundity: Multiple Fathers
Multiple heats aren't the only interesting thing about Fluffy's reproductive system. She's also able to have kittens with different fathers, which is known as superfecundity. Being pregnant doesn't stop her heat cycle, and 10 percent of female cats come into heat again between the third and sixth week of pregnancy. Although it's rare, it's possible for your kitty to carry fetuses of different ages from different matings in different heat cycles, which is known as superfetation.
When in heat, your cat can have multiple eggs that are released over the course of her cycle, which can range from three to 20 days. Because she's in heat, her instinct tells her to look for a mate. She will search by looking for markers, such as urine, and signal her intention to mate by rolling around and making loud yowling noises. The number of fathers and kittens will depend on how many eggs are released during her heat cycle, when she mates and who she mates with.
If you are trying to breed Fluffy with one particular male, keep her contained in a room for at least 24 hours with her chosen mate. You should also keep her inside during the rest of her heat cycle to make sure she doesn't seek out additional male attention. Otherwise, the best course of action is to make sure your furry friend is spayed. Her efficient reproductive system can lead to too many kittens. And as the ASPCA notes, many healthy cats are euthanized because there aren't enough homes for them all. If you're concerned about Fluffy's reproductive status, talk to your vet or local humane society about getting her spayed.