Do Male Cats Have Nipples?
If you’ve ever seen a mama cat and her nursing kittens, it probably comes as no surprise that nipples play an important role in helping kittens grow big and strong. But if you have a boy cat and run your hand down his tummy, you might feel tiny points and wonder what they are.
Do male cats have nipples?
Dr. Mahmoud Mansour, a professor of veterinary anatomy at Auburn University, says nipples on male mammals are somewhat of an “evolutionary quirk”— and one with little to no real function. This article will explain whether male cats have nipples, where to find them, and how to spot if something is amiss.
Cat Nipple Anatomy: Understanding the Basics
Almost all mammals have nipples, and cats are no exception. The nipple itself is a tubular structure of thick skin and special ducts (which are collapsed in male and young female cats). Below the exposed nipple are the mammary glands, which you probably won’t notice unless your healthy cat is pregnant or nursing.
According to Dr. Rafael Senos, professor of Veterinary Anatomy at Cummings School of Veterinary Medicine at Tufts, this basic structure “is similar across the species and sexes.”
The mammary glands of cats, and therefore their nipples, are typically found in two parallel rows. They run along a cat’s underside, starting at the chest (thoracic region) to the belly (abdomen region) and ending near the groin (inguinal region).
Do Male Cats Have Nipples?
Yes, male cats have nipples. Most cats, male or female, have anywhere from four to ten nipples. However, on male cats, they can be difficult to see, Dr. Mansour says.
In fact, when female cats are spayed at a young age, their nipples won’t fully develop like the nipples of a queen (sexually mature intact female cat) would. So, a boy cat’s nipples might look a lot like the nipples of a spayed female — small and difficult to find.
But there are some big differences between male and female nipples in cats. Namely, healthy male cats cannot produce milk (more on this later). “The nipples and mammary glands remain rudimentary throughout the life of a male cat,” Dr. Senos says.
In other words, the nipples and mammary glands of male cats aren’t fully developed. They stop developing because male cats don’t produce prolactin, the female hormone required to mature the mammary glands and produce milk.
Cats can have two pairs (four nipples) in the thoracic region, two pairs (four nipples) in the abdominal region, and one pair (two nipples) in the inguinal region, totaling ten nipples. However, the average for cats – both male and female – is six to eight nipples. Some male cats may have fewer nipples than females.
Although most cats have an even number of nipples, it’s not uncommon for them to have an odd number. In this case, the nipples in each parallel row aren’t symmetrical with each other.
Why Do Male Cats Have Nipples?
According to Dr. Mansour, the nipples of a cat develop before anatomical sex is determined.
Specifically, adds Dr. Senos, “the fetus develops a mammary ridge by the 25th day of gestation and five days later, the ridge differentiates into four or five pairs of nipples.”
After this, sex-determining genes kick in and your fuzzy furball continues to develop as a boy or a girl. The nipples just happen to be there, whether the now-gendered cat needs them or not.
The bottom line is that, like our appendix, the nipples of male cats serve no known biological function.
Can Male Cats Produce Milk?
A healthy male cat shouldn’t produce milk. But in rare cases, male cats can produce milk. The condition is called galactorrhea, and it’s so rare in cats, records of the condition are sparse. But, it is documented in a 2017 study titled “A Rare Case of Galactorrhoea in a Domestic Tom Cat” .
According to the study, “milk secretion in male mammals is induced by a surge in prolactin and can occur spontaneously.” As for the tomcat in the study, excessively grooming his underside caused overstimulation of his nipples, which in turn, resulted in a surge of hormones. He was treated with oral medication and by day five, most of his symptoms cleared with full recovery by day 14.
Some male cats are purposely treated with female hormones to reduce behavioral issues, like urine marking. While lactation isn’t mentioned as a side effect of these drugs, they are linked to other nipple problems in male cats  .
Possible Nipple Problems for Male Cats
If you haven’t already, it’s a good idea to gently feel around for your cat’s nipples. Recognizing what’s normal means having the ability to quickly act when something doesn’t look or feel quite right.
Here’s a brief description of conditions that can affect a cat’s nipples and mammary glands, according to Dr. Douglas Mader, a triple board-certified veterinarian and author volunteering his services throughout Florida:
Mammary Gland Cancer
“Mammary tumors are rare in male cats,” Dr. Mader says. “But both intact and neutered [male cats], have been identified with malignant mammary gland tumors.”
Because of its high occurrence in female cats, mammary gland cancer remains the third most common cancer type in cats.
It’s most prevalent in domestic shorthair, Persian, and Siamese cats. And in males, one-third of the cats diagnosed with mammary gland cancer were treated with female hormones at some point in their lives.
“Sadly, the course of disease progression in affected males is similar to that seen in female cats, with the prognosis usually less than one year after diagnosis,” Dr. Mader shares.
Feline Mammary Hyperplasia
Also called mammary fibroadenomatous hyperplasia or MFH for short, this is a non-cancerous growth of the mammary glands typically caused by hormonal stimulation . Although a 2018 described an occurrence of MFH in a male cat, this condition overwhelmingly occurs in female cats.
“It can be uncomfortable for the cat,” Dr. Mader says. Plus, the enlarged mammary glands might be accompanied by discharge from the nipples, such as milk, serum, blood, or pus — although milk secretions are rare.
Without treatment, secondary underlying infections could set in, and surgery of the mammary glands may be required. But, Dr. Mader adds, when treated promptly (sometimes with a spay, neuter, or discontinuing female hormone-based therapy), the condition typically reverses without the need for invasive surgery.
Mastitis is inflammation of a mammary gland, often due to ascending infection or excessive milk accumulation. “One or more glands become inflamed due to bacteria residing inside the gland,” Dr. Mader explains. The underside of your cat might be swollen, sore, and there may be secretions . “When caught early and identified, mastitis can be treated,” he adds. Most cases of mastitis occur in postpartum female cats if their kittens are weaned suddenly.
Of course, your veterinarian is the only one who can give a proper diagnosis. So, “if you see anything abnormal about your cat’s nipples – male or female – such as thickening, discharge, lumps and bumps, or bleeding, take your cat to the veterinarian immediately for diagnosis and treatment,” Dr. Mader says.