Mites on dogs come from several different sources depending on the type of mite. Some are passed from mother to puppy within hours of birth and live quietly on the skin for life. Others are picked up from wildlife, other pets, contaminated environments, or shared spaces like kennels and groomers. Understanding which mite your dog has tells you exactly how they got it.
Mites Passed From Mother to Puppy
The most common mite found on dogs, Demodex canis, is transferred from mother to puppy during nursing within the first 72 hours after birth. This happens through direct skin-to-skin contact as puppies press against their mother’s face and body while feeding. Nearly all dogs carry small numbers of these mites in their hair follicles throughout their entire lives, and in most cases, the mites never cause any problems.
Demodex mites are considered part of the normal skin flora, similar to the bacteria that live harmlessly on human skin. A healthy immune system keeps their population so low that standard testing often can’t even detect them. The trouble starts when something weakens a dog’s immune system, allowing the mites to multiply out of control. In puppies, this sometimes happens because their immune systems are still developing. In adult dogs, the triggers include illness, malnutrition, aging, or medications that suppress immune function. The mites were always there. What changed is the body’s ability to keep them in check.
Because Demodex mites transfer so early in life and don’t survive long away from a host, adult dogs don’t catch them from casual contact with other dogs at the park or boarding facility. If your adult dog develops demodectic mange, the mites almost certainly came from their mother years ago.
Mites Picked Up From Other Animals
Sarcoptic mange mites (the ones that cause intense, relentless itching) come from direct contact with an infested animal or from sharing the same environment. Dogs most commonly pick them up from wildlife. Foxes, coyotes, and other wild canines are major carriers, and a dog doesn’t need to touch one directly to get infested. Mites spread through shared spaces: a den entrance a fox used, a spot under a deck where a coyote rested, or an area near an artificial feeding site where wildlife congregates.
These mites can survive off a host for 24 to 36 hours at normal room temperature and humidity. That window is long enough for a dog to pick them up from contaminated bedding, a shared kennel, or even furniture where an infested animal recently rested. Research on wildlife transmission has shown that indirect spread through shared dens and resting sites is likely the dominant way these mites move between animals, even more so than face-to-face contact.
Sarcoptic mites are highly contagious between dogs, so multi-dog households are especially vulnerable. If one dog brings them home, the others will likely get them too.
Ear Mites From Cats and Other Pets
Ear mites (Otodectes cynotis) most often come from cats. While these mites infest both dogs and cats, cats are the more common carriers, particularly free-roaming and stray cats. Dogs typically pick them up through direct contact with an infested cat or, less commonly, from another dog.
The mites live primarily in the ear canal but can also be found on the body surface of infested animals, which makes casual physical contact sufficient for transmission. Dogs in rural areas or those with access to outdoor cats face higher risk, as do dogs in households where cats come and go freely. Wild carnivores can also carry ear mites, though domestic cats remain the primary source for pet dogs. If your dog suddenly develops dark, crumbly ear discharge and starts scratching at their ears, contact with a cat (even a brief encounter) is the most likely explanation.
Mites From Kennels, Shelters, and Groomers
Cheyletiella mites, sometimes called “walking dandruff” because they cause visible flaky skin, spread in places where many dogs are in close quarters. Animal shelters, breeders, boarding kennels, and grooming facilities are the most common sources. Dogs contract these mites through direct contact with an infested dog or through shared brushes, bedding, and surfaces.
Unlike Demodex mites, Cheyletiella doesn’t live naturally on dogs. Every case traces back to an environmental exposure. If your dog develops unusual dandruff-like flaking shortly after a stay at a kennel or a grooming appointment, Cheyletiella is worth investigating.
Why Some Dogs Get Infestations and Others Don’t
Two dogs can visit the same park and only one develops a mite problem. The difference usually comes down to immune function and overall health. For Demodex, this is especially clear: the mites are already present on virtually every dog, and only dogs with compromised immunity develop visible disease. Puppies, elderly dogs, dogs undergoing chemotherapy, and dogs with chronic illnesses are the most vulnerable.
For contagious mites like Sarcoptes and Cheyletiella, exposure level matters more. A dog that briefly passes a fox on a trail is at much lower risk than one that regularly investigates fox dens. A dog that visits a well-maintained groomer is at lower risk than one staying in an overcrowded shelter. The intensity and duration of contact, whether direct or through a contaminated environment, determines whether enough mites transfer to establish an infestation.
How Vets Identify the Source
Figuring out which mite your dog has (and therefore where it came from) requires a skin scraping. A vet gently scrapes a small area of skin with a blade, collects the material onto a glass slide with mineral oil, and examines it under a microscope. The scraping can be superficial for mites that live on the skin surface, like Sarcoptes and Cheyletiella, or deep enough to reach the hair follicles where Demodex hides. The scraped area looks like a mild abrasion afterward, similar to a skinned knee.
For ear mites, the process is simpler. A sample of ear debris examined under a microscope reveals the mites directly. Sarcoptic mange can be trickier to confirm because the mites burrow deep and are present in relatively small numbers, so a negative scraping doesn’t always rule it out. In those cases, vets sometimes treat based on symptoms and see if the dog improves.
Can Dog Mites Spread to People
Sarcoptic mange mites can temporarily transfer to humans through close contact with an infested dog, causing itching and irritation on the forearms, chest, abdomen, and thighs, wherever skin touched the dog. However, these mites strongly prefer their canine host and can’t complete their life cycle on human skin. The infestation is self-limiting, meaning it resolves on its own once the dog is treated. Unlike human scabies, the mites don’t form the deep burrows typical of a true infestation, and the symptoms are shorter-lived.
Cheyletiella mites can also cause temporary itching in people who handle infested dogs. Demodex mites are species-specific and pose no risk to humans. Ear mites rarely affect people but can occasionally cause mild, temporary skin irritation.