Exploring my dog’s spring tick burden — bringing scientific exploration into the home

While eating dinner several weeks ago, my wife and I noticed a small dot moving up the wall of our house. My hopes that it was just a carpet beetle or stink bug vanished as I got closer and saw eight legs and patchy white colorations across its back. An American dog tick. We immediately combed through the hair of Ralphie, our Australian shepherd, and found four more.

Prior to moving to South Bend, Indiana, I had never seen a live tick before. Ticks were certainly active in Colorado, and we always learned how to check for them when camping in the mountains, but I had never encountered one. Now, they are a regular occurrence of my daily life.

Ticks (order: Ixodida) are ectoparasitic arachnids with quite the complex life cycle that lasts two to three years. After hatching from egg, they go through three life stages: larvae, nymphs, and adults. At each stage, they require a blood meal. As larvae, they tend to feed on smaller animals such as rodents, and as nymphs and adults, they tend to feed on larger animals, such as deer, cattle, and humans. (Side note: while we typically think of ticks feeding on mammals, many will feed on birds and reptiles as well!)

When female ticks are looking for a good host to bite, they are partaking in questing. Questing ticks will climb to the top of vegetation and wait with their legs out, ready to grab onto (or be drawn to through static electricity) a passing host. They feed on the host’s blood for several days before falling off and use the blood to either grow into their next life-stage or lay eggs.

As Ralphie is quite the active, curious sniffer, he is constantly running into grass and bushes. As such, we need to do a deep tick check all over him every time we take him outside. While the dog owner in me is always concerned, the entomologist in me is excited at his ability to sample the local tick populations. This year, I decided to start quantifying the number of ticks we found on him after every walk. Here are my findings from the first month of measuring.

Ralphie (and likely several ticks!)

How many ticks did we find?

From March 25 to May 5, 2026, we found 190 total ticks on Ralphie after walks (two walks per day). Of these, 164 were blacklegged (deer) ticks, and 26 were American dog ticks.

Blacklegged ticks are the most well known tick in the United States due to their ability to transmit the bacteriae that cause Lyme disease, anaplasmosis, and several other human diseases. Lyme disease is the most common vector-borne disease in the US with at least over 400,000 cases reported annually, and it presents itself with flu-like symptoms (but can be distinguished by the bullseye rash). If Lyme disease is caught early, it can be treated with antibiotics. While there is no vaccine in humans, there is a vaccine for dogs that is recommended in Lyme heavy areas (like South Bend, IN).

American dog ticks are bigger and a bit creepier looking than blacklegged ticks, and they have the ability to transmit the bacteria that causes Rocky Mountain spotted fever. While fairly uncommon, Rocky Mountain spotted fever can cause severe complications. However, like Lyme disease, it can be treated with antibiotics if detected early enough. If you are experiencing symptoms after being bitten by a tick, make sure to contact a medical provider immediately.

Blacklegged and American dog ticks are the most common ticks in Indiana, so it is not surprising these are the only species we found on Ralphie. There are estimated to be 15 species of tick in Indiana, however, including the Lone Star tick and the brown dog tick.

Tick abundance is higher in more natural areas

In South Bend, we take Ralphie on a wide variety of walks, from county parks to walking the campus of Notre Dame. As tick populations need wildlife and vegetation to proliferate, their abundance is dependent on land-use type. Not surprisingly, the number of ticks per walk varied significantly with land-use type (p < 0.001, chi-squared = 16.124; statistical model information included at the end of this post).

On walks in neighborhoods or on campus, we tended to find <1 tick per walk. However, on walks where the trails go through natural spaces, we tended to find >2 ticks per walk. After one walk alone at St. Patrick’s County Park, we found 21 ticks on Ralphie.

Figure 1: Mean number of ticks per walk (with 95% confidence intervals) found on Ralphie by land-use type. Campus represents a university campus, neighborhood represents residential areas, and park represents nature trails in county parks.

It is important to note that regardless of landscape type, we found ticks on Ralphie. While the abundance trended towards being greater in natural areas, the risk was still there regardless of land-use.

Tick abundance increases with temperature

Ticks, like all arthropods, are ectotherms (think, “cold-blooded”). This means that they rely on the temperature of their environment to regulate their body temperature, rather than relying on internal metabolism like endotherms like us do. As such, ticks (and other disease vectors such as mosquitoes) exhibit temperature dependence.

At cold temperatures, we would expect the ticks to be far too cold and slow to exhibit questing behaviors, but, as temperatures warm, we might expect the tick questing to increase as well. (Note: we have not yet experienced temperatures above 85℉ in South Bend, but we may expect tick abundance to go decrease again when it gets too hot for them)

Figure 2: Mean number of ticks per walk (with 95% confidence intervals) found on Ralphie in response to ambient temperature during the walk.

On walks where the temperature was below freezing (32℉), we observed 0 ticks on Ralphie. However, as temperature increased, we observed a linear increase in the number of ticks per walk (p = 0.008, chi-squared = 7.027).

We observed an average of 1 tick per walk when the temperature was between 30℉ and 50℉, 2.7 ticks per walk when between 51℉ and 70℉, and 5.4 ticks per walk when above 71℉.

What can we take away from this?

Arthropods like ticks and mosquitoes are environmentally sensitive, so the diseases they transmit depend on environmental conditions as well. By using metrics like temperature and land-use type, we can predict when and where we are most likely to come into contact with these biters.

When you are outside, particularly in warm temperatures and near vegetation, wear bug-spray and check for ticks often. If you have a dog or cat in these areas, I highly recommend using veterinarian-approved tick preventatives such as chewables and collars (and definitely get them vaccinated for Lyme disease and get regular tick-borne disease panels!)

If you are interested in learning about the spatial and temporal dynamics of ticks in your region, I highly recommend exploring the tools on TickEncounter. You can choose your region and month to view what tick species and stages you’re most likely to encounter! If you are interested, the lab will also identify ticks for you based on pictures, and they even have resources listed for if you are interested in having your ticks tested for disease agents. (I’m also more than happy to answer questions too!)

Since ticks are attracted to us and our pets, they are an easy, powerful, and very relevant arthropod system to apply citizen science to! As the year progresses, I’m excited to see how other factors, such as humidity and the life stage of the tick, factor into the ticks acquired on walks.

Statistical model information

For those curious about the statistical model I used to analyze this data, here is that information! I used the *glmmTMB package in [R](https://www.r-project.org/) version 4.5.1. I included temperature, land-use type, and time of day as fixed effects, as well as an ar1 autocorrelation structure to account for temporal autocorrelation. The response variable was the total number of ticks collected on each walk, and I used the nbinom1 family (after using Akaike information criterion to select between poisson, nbinom1, and nbinom2). Significance was assessed using the [car](https://cran.r-project.org/web/packages/car/index.html) package. Model predictions were generated using [sjPlot](https://strengejacke.github.io/sjPlot/), and plots were assembled using [ggplot2](https://ggplot2.tidyverse.org/)*.

Patrick Heffernan is a PhD candidate at the University of Notre Dame studying vector-borne disease ecology. Prior to Notre Dame, he studied Ecology & Evolutionary Biology and Philosophy at CU Boulder, and he was the proud president of Literary Buffs, the English department’s creative writing club. If you’re interested in connecting, please do so on LinkedIn or Bluesky.

Music recommendation: Dizgo’s 3/21/2026 Globe Hall full set