Which Have More Bacteria in Their Noses: Dogs or Kids?


Age 9 at time of project | Charlottetown, Prince Edward Island

P.E.I. Science Fair Top Project Award

We wanted to know what lives in our noses. Kids get sick with stuffy noses and we wondered what was making it happen. Then we figured out that there were more things in our noses that we did know about, like different kinds of bacteria.  We thought it would be interesting to compare kids noses to other noses. We decided that dogs should have more bacteria in their noses compared to kids because they use their noses in different ways such as sniffing the ground and other dirty places.


Our question was: which have more bacteria in their noses - dogs or kids? We hypothesized that dogs have more bacteria in their noses than kids.


We noticed that kids like us often had stuffed up noses from illness, and we wanted to know what germs made us sick.   We wondered what specifically was making it happen. Apart from infections many things can cause our noses to be stuffed up such as allergies, crying or even cold weather. Bacteria, viruses and boogers can live in your nose. Boogers are made of mucous. Mucous is the slimy stuff that is made in your nose. It is very important to your body. If you were in a dusty, dirty cabin, the mucous would help trap the dirt from the air. The mucous not only protects the lungs from the dirty air but contains antibodies which help protect your body from infection. Our nares are the two holes that let us breathe air into our nose. They are also called nostrils. They also help us smell (kidshealth.org, WebMD.com).

Viruses can cause colds and the flu. 200 different viruses cause colds. Rhinovirus is the name of the virus that most often causes the common cold (kidshealth.org). The flu is caused by influenza virus.  Viruses are so small you can’t see them without a microscope.  Viruses range in size from 20-400 nanometers in diameter (NCBI website).   

There are 2 264 types of bacteria that live in your nose. The most common kind is Staphylococcus. Other kinds are called Cornyebacterium and Streptococcus (National Geographic, January 2013).  There are good and bad bacteria.  Some bacteria lives in your nose and helps keep you healthy so some bacteria live in your nose all the time even when you’re feeling fine.  Bacteria can cause sickness in different ways such as multiplying rapidly, destroying cells and tissue, releasing toxins, and interfering with the normal functions of your body (NCBI website).


Sterile swabs

Plates with agar

5 dogs

5 kids (6-10 years old, male and female)

We obtained our sterile swabs and plates with agar from the medical microbiology laboratory at the Queen Elizabeth Hospital.  Our friends and neighbours volunteered themselves and their dogs to be our test subjects.  All subjects were well at the time of the experiment.  


Swab 5 kids and 5 dogs noses

Rub swabs on petri dishes with agar

Put dishes in a dark warm place for 3-4 days

Take pictures of the bacteria growing

Count bacteria types and number of colonies

To make our experiment fair, we swabbed 5 dogs and 5 children’s noses. They were equal groups. We swabbed the children’s noses the exact same way. We smoothly rolled the swab in the kids nares. Some kids were worried about it so we told them what would happen. This is what we said, “You have to hold the swab right on the pink handle so you don’t put any of your own bacteria on the swab. Then we would lightly roll the swabs in your nares.” Then we would take the swab and put it in a tube. Next we put them in a room at normal room temperature (approximately 20 degrees celsius).

We had to do the dogs’ noses a different way because some dogs were scared and some dogs were small (Figure 1). The small dogs’ nares were too small to fit the swab inside them. We had to rub the swab on the tip of their noses if they were scared. We did that because we couldn’t get too close without scaring them. We also left those swabs at a normal room temperature (approximately 20 degrees celsius).

After that, we went to Dr. German’s office and he showed us what to do on the agar plates (Figure 2). We rubbed the swabs on the agar plate three times up and down. Then we used the loop to rub it back and forth 15-30 times. The agar plates were left in a dark warm room together for the same amount of time. We took pictures of each agar plate to show how they were growing.


Dr. German taught us that different colonies of bacteria can be identified in many different ways including shape, size, and color. He helped us count the number of colonies on each plate.

Table 1. Total number of kinds of bacteria = different colonies

Table 1. Total number of kinds of bacteria = different colonies


Dogs did have more bacteria in their noses than kids. We think dogs have more bacteria in their noses because they sniff with their noses right to the ground. Dogs likely use their noses in many different ways compared to humans.  The things they smell are not always clean. Dogs don’t clean themselves the same way we do. We take showers and wash with soap and water. Soap and water kills bacteria on our bodies. Dogs lick themselves to keep clean.


Our hypothesis was correct. We learned a lot about bacteria and how viruses cause colds. We hope we can learn more on this topic. It was very interesting, especially when we saw what bacteria look like. 


Dr. Michael Fong, Ear Nose Throat Specialist, Charlottetown, PE

Dr. Greg German, Medical Microbiologist, Charlottetown, PE




KidsHealth.org. Why does my nose run?  https://kidshealth.org/en/kids/nose-run.html  

National Geographic, January 2013

Science Kids website

Factmonster.com website

National Center for Biotechnology Information.  What You Need to Know About Infectious Disease.  https://www.ncbi.nlm.nih.gov/books/NBK209710/

WebMD. The truth about mucous.  https://www.webmd.com/allergies/features/the-truth-about-mucus#1

Mayo Clinic. Common Cold. https://www.mayoclinic.org/diseases-conditions/common-cold/symptoms-causes/syc-20351605



Aiden went to elementary school at West Royalty Elementary where he competed his science fair project on bacteria.  He subsequently attended Queen Charlotte Junior High School and will be attending Colonel Grey High School in the Fall of 2018. He enjoys going to the gym and pursuing his musical interests.


Jordan Jenkins is a now 16 year old, residing in Charlottetown.  At the time of the fair he was attending West Royalty Elementary, eventually moving on to Charlottetown Rural. He’s kept his nerdy love of science through the years, and is an aspiring Chef and 3D Artist.