Zombies in the Hills

February 16, 2026

A zombie ant. Photo © C. Hunter

By Cameron Hunter, AWA Conservation Specialist

Read the PDF version here.

Video narrated by Dr. Cam Goater and filmed by Cameron Hunter detailing the parasitic cycle.

In May 2025, prior to working at AWA, I had a chance to collaborate with AWA as a freelance photographer and videographer, capturing a very eventful and personally insightful Bioblitz at Cypress Hills Interprovincial Park. From bats, birds, and botany, to bugs, beetles, and butterflies, I strived to document as much about the people at the bioblitz, and the biodiversity of a unique park in Alberta, as I could. Sleep was lost, but the end result was worth it

As I arrived at the Aspen Ridge Hut campsite on the first afternoon of the bioblitz, I was greeted by the AWA team. Many eager individuals were looking to start noting their observations; some were identifying unfortunate grasshoppers in the grills of nearby vehicles, others were setting up their lodgings for the weekend, and some were preparing moth nets and pheromone traps. Before I had even moved my bags, I was greeted by a fellow Cam, Dr. Cam Goater, from the University of Lethbridge, who studies the ecology and the evolution of host-parasite interactions. After a quick introduction, Cam said a word I was not expecting to hear that weekend: “Zombies.”

My ears perked up, and as I inquired if I heard him correctly, he affirmed he indeed said zombies — zombie ants, in fact — and promised me he would get me a photo before the weekend was over. It wasn’t even five minutes later, and there I was lying on the ground photographing an ant on a single blade of grass that had a parasite in its brain controlling its mandibles.

I was hooked.

Dr. Goater explained the process of this zombification as I remained on the ground photographing the ants. The species we were observing was Formica aserva, a common brooding ant of the Formica family. In the Cypress Hills, there are colonies of these ants that have parasites in them called trematodes (Dicrocoelium dendriticum), commonly known as flukes. He explained to me how these flukes are found predominantly within the ants’ stomach, but there is always one individual parasite found within the regions of the brain that control the actions of the mandibles.

Dr. Goater continued to observe the area as I remained fixated, explaining further that there were most likely snail shells to be found around where we were stationed. Whereas the ants are a required intermediate host in the life cycle, so too are land snails. In an ecological quirk, ants become infected when they ingest fluke larvae that are released onto pasture from infected snails. In the Cypress Hills, the snail is Oreohelix subrudis — the common mountain snail. The bizarre life cycle of the fluke is completed when the final hosts ingest infected ants that are attached to plants like dandelion, flowers, grasses, and other greenery. Dr. Goater and his students have shown that the livers of most white-tailed deer, elk, and cattle in the Cypress Hills contain adult worms.

After taking photos of the ants, I unpacked my gear and photographed the evening’s talks and introductions, then headed out to photograph moths late into the night, making sure to curb my enthusiasm so that I would be rested for the next day’s events. The next morning, I joined talented botanists on their trip to find a rare aster, Erigeron radicatus, commonly named tap-rooted fleabane, within the rocky bands of Cypress Hills that overlooked Reesor Lake. I constantly searched for zombified ants on the tips of grass and dandelions, all while attempting to decode the Latin names of all the plants we came across that the botanists identified around me. We also checked for invasive species throughout the day, closely inspecting the shores of Reesor lake for invasive plants and invertebrates.

The evening was filled with bat nets and more moths, although I could not bring myself to stay up late enough for the bat that was caught within the mist nets (which were being monitored for white-nose syndrome). I had plans to be up early the next morning to meet Dr. Goater to film a short video about the ants he introduced me to earlier. After a full day spent hiking with the botanists in search of the aster, as well as identifing birds, learning and photographing forest orchids, North America’s most toxic plant, the water hemlock, and searching for common poorwills late at night on backroads, my mind was racing, full, and tired from the day’s activities.

On the second morning, before the sun rose too high in the sky, I met up with Dr. Goater in Elkwater to record a short video about the parasitic system that exists at a nearby zombie ant research station, where there is a conveniently located ant colony that can be monitored and studied closely, due to its close proximity to the town and lodgings.

Dr. Goater was kind enough to do an interview for AWA about the bioblitz, describing the diversity of the area with great detail and passion, and then we recorded another video, this time explaining the parasitic process and how these ants play a key role as an intermediate host.

We arrived early in the morning to record this video so that we could showcase the behaviours of infected ants, and a unique aspect of said behaviors: that the parasite can activate certain ant behaviours like a switch. The ants function normally until the cooler times in the morning, when they get “chauffeured” out onto nearby grasses, dandelions, flowers, and horsetails by the parasite in their brain. The ants latch onto the tips of these plants with their mandibles, and then as the sun comes out, the parasite releases their mandibles to avoid overheating the host, and the ants leave and return to the colony, until the very next day, when the attach/detach process is repeated. Eventually, white-tailed deer and elk that graze the grasses and flowers will unknowingly consume the ants, and in turn, the parasite, which is how the parasite ends up in its final host.

This ant colony that Dr. Goater and his team were monitoring was encased in a dead tree stump, and as you might expect, there were thousands of ants constantly moving in and out of the colony and bringing new information to their sisters. Littering the ground surrounding, and even on, the colony were little helixes of snail shells — evidence of the potential passing of parasites from the snails to ants. Nearby grasses and flowers were speckled with rufous dots; these are ants with mandibles locked, in hopes of a peckish passing ungulate. Plants nearby showed the presence of grazing deer; the headless stems of dandelions were spotted only feet from the ant colony. The scene was a clear depiction of fluke transmission at an ant nest site, and it was happening here in Cypress Hills.

Dr. Goater brings students to the Cypress Hills Provincial Park every year in his field biology course, studying the relationships between parasites and hosts. He and his students look at different parasites that affect minnows, viruses present in salamanders that impact amphibian populations throughout Canada, and parasites within local fish populations. They are hoping to learn more about how these parasites impact their hosts’ ability to see, smell, think, and move through the world.

There was an abundance of passionate individuals like Dr. Goater who took part in the Cypress Hills bioblitz. More than 70 citizens, educators, scientists, communicators, naturalists, and conservationists all came together to capture the natural life that exists within Cypress Hills, a unique sky island ecosystem nestled within the southeastern corner of Alberta’s prairies. I was hooked by this experience, and I’ve since returned to Cypress Hills and the prairies reaching out from its base to see more of the biodiversity hosted within the park and surrounding landscape.