Cats have nipples for the same reason all mammals do: to feed their young. Mammary glands produce milk, and nipples are the delivery system. What makes this question interesting is that every cat has them, male and female alike, and the number isn’t even consistent from one cat to the next. Most cats have six to eight nipples, but some have four, others have nine or ten, and all of those counts are perfectly normal.
What Nipples Do in Female Cats
In a nursing mother cat, nipples are the endpoint of a surprisingly complex system. Each nipple contains 7 to 20 tiny openings that deliver milk directly to the surface. Unlike cows and goats, cats don’t have a collecting reservoir inside each gland. Instead, milk flows through separate small canals straight to the kitten’s mouth.
Milk production kicks in when progesterone levels drop sharply at birth. A mother cat produces milk for roughly three to four months, though kittens are typically weaned around 10 weeks. How much milk she makes depends on litter size. A cat nursing one or two kittens produces about 1% of her body weight in milk per day during the first week. A cat with six kittens ramps up to over 3%, and by weeks two through four, output climbs even higher.
Cat milk is more than calories. It carries antibodies that protect a kitten’s gut lining, growth factors that support development, and antimicrobial compounds. Kittens show a strong preference for the rear nipples within 12 hours of birth, spending about 40% of their suckling time there compared to just 5% on the front pair. Interestingly, the nutritional content between front and back glands is nearly identical, so the preference likely comes down to accessibility and comfort rather than a richer milk supply.
Why Male Cats Have Them Too
Male cats have nipples because nipple development begins in the embryo before sex differentiation takes place. Every kitten, regardless of its future sex, starts building mammary tissue on the same early timeline. Once a male embryo’s testes begin producing testosterone, that hormone reshapes many parts of the body, but in most mammal species it simply never reaches the developing mammary glands in a way that would dismantle them.
A 2025 study clarified why this happens. In species where males lose their nipples during fetal development (like mice), testosterone activates specific receptors directly in the mammary tissue, triggering cell death and nipple destruction. In species where males keep their nipples (like guinea pigs, cats, and humans), those same receptors are inactive in the mammary area. The testosterone is circulating, but the developing nipple tissue can’t “hear” the signal telling it to disappear. Cell proliferation continues normally, and the nipple forms.
This means male nipples aren’t a fluke or a leftover. Keeping nipples is the default across mammals. The few species whose males lack them are the exceptions, not the rule.
How Many Nipples Cats Have
Cats typically have four pairs of mammary glands arranged in two rows along the belly: two pairs near the chest (thoracic) and two pairs closer to the hind legs (abdominal). That gives most cats eight nipples total. But variation is common. Some cats have six, others have an odd number like five or seven, and a few have more than eight. None of these counts signal a health problem.
Male and female cats follow the same range. A male cat might have four nipples or eight or anywhere in between. The nipples on a male cat are small and can be hard to spot under fur, but they’re there.
Mammary Health Worth Knowing About
Because cats have functional mammary tissue, that tissue can develop problems. In nursing mothers, the most common issue is mastitis, an infection of one or more mammary glands. Early signs are subtle: kittens may not gain weight as expected, and the gland might look slightly swollen. As it progresses, the gland becomes red or purple, painful, and visibly inflamed. Milk from an infected gland can appear cloudy, thickened, or contain blood. In severe cases, the tissue turns dark purple or black as it loses blood supply, and the cat may develop fever, stop eating, or become lethargic.
Mammary tumors are also a real concern in cats, and they tend to be aggressive. The rear glands are more commonly affected. Spaying has a significant protective effect, but timing matters enormously. Cats spayed before 6 months of age see a 91% reduction in mammary cancer risk compared to unspayed cats. Spaying before 1 year still offers an 86% reduction. After that, the benefit drops sharply. Spaying between 13 and 24 months provides only about an 11% reduction, and spaying after age 2 was actually associated with a higher risk than not spaying at all in one study.
For cat owners, this means those small, easy-to-overlook nipples are worth a periodic check. Running your hand along your cat’s belly and feeling for any hard lumps, swelling, or discharge near the mammary line is a simple habit that can catch problems early, when they’re most treatable.