Indiana’s Gray Foxes Are Declining. Southern Indiana May Hold Clues to Why.

Gray foxes are built to disappear.

They spend much of their time around woods and thick cover, move largely when people are not watching and possess one ability that separates them from Indiana’s other wild canids: gray foxes can climb trees. [5]

Lately, though, wildlife biologists have been dealing with a different kind of disappearance.

Gray fox populations have been declining across Indiana and several other Midwestern states. Long-term harvest records, hunter observations and field studies all point in the same general direction, even though none provides a simple statewide count of how many foxes remain. [1]

A large Indiana research project is now giving biologists a much better look at the problem. Instead of finding one clean explanation, the researchers found several warning signs at once.

The Decline Is Real. The Exact Size of It Is Harder to Measure.

Gray foxes are difficult animals to count. They are secretive, occur at relatively low densities and do not lend themselves to a neat statewide census.

That means much of the evidence for decline comes from indicators: hunter observations, harvest records, fur-buyer data and other long-term monitoring.

Those measures have limitations. Pelt prices change. Hunting and trapping effort changes. Reporting methods change. The authors of the new Indiana study explicitly warn that harvest numbers should be used as long-term indices rather than treated as direct population counts. [1]

But when several independent indicators move in the same direction across multiple states, the pattern becomes harder to dismiss.

The 2026 Wildlife Monographs study describes substantial long-term declines in Midwestern harvest and observation indices. Indiana DNR likewise says the state’s gray fox population has declined during recent decades. [1] [4]

Why Southern Indiana Stood Out

The Indiana project compared two very different parts of the state.

The central study area covered Bartholomew, Decatur, Johnson and Shelby counties. It was dominated by private land, with about 58% row-crop agriculture and 17% forest and woodland.

The southern site covered Crawford, Harrison, Orange and Perry counties. About 61% was forest and woodland and only 13% was agricultural cropland. It also included substantial public land, including Hoosier National Forest, Harrison-Crawford State Forest, O’Bannon Woods State Park and the Patoka Lake area. [1]

Researchers captured 32 gray foxes overall and fitted 29 with radio collars. After collar failures and an early mortality were removed, usable tracking data came from 24 foxes in the southern study area and only one from the central study area. [1]

That difference is striking, but it needs a caution label.

Capture success is not the same thing as a population survey. Differences in access, trapping conditions and where animals happened to occur can influence which foxes end up in a telemetry study. The researchers did not claim that the 24-to-1 result represents the actual population ratio between southern and central Indiana.

A separate 2026 study, however, points in the same general direction. Researchers used confirmed community observations to model gray fox distribution statewide. Their best-performing models predicted higher probabilities of presence near the northern and southern ends of Indiana and lower probabilities across the agriculture-dominated center of the state. [3]

Forest, mixed wooded cover and forest-scrub edges were among the features associated with higher predicted presence.

A Fox Built for Edges — But Not Every Edge Is Good Habitat

One of the more interesting findings sounds contradictory at first.

Gray foxes selected against row-crop agriculture. Yet their probability of use was often greatest near agricultural cover, buildings and roads. Use dropped substantially as foxes moved more than about 100 meters away from those features. [1]

The distinction is between using an edge and using what lies on the other side of it.

The researchers also found that gray foxes used developed roads and low-intensity developed areas in some circumstances while avoiding the highest traffic volumes. [1]

That makes the word fragmentation tricky.

A wooded corridor bordering a field, a brushy opening inside a larger forest and a five-acre woodlot isolated between highways and hundreds of acres of corn are all technically forms of edge. Ecologically, they are not the same thing.

Indiana Gray Foxes Are Covering a Lot of Ground

The GPS collars exposed another clue.

Indiana DNR summarizes the average gray fox home range from the project at roughly 3.5 square miles. The peer-reviewed study estimated seasonal utilization areas averaging about 871 hectares outside the reproductive season and about 955 hectares during the reproductive season — approximately 3.4 and 3.7 square miles. [1] [2]

Those estimates are large compared with many previously published gray fox studies. The authors cite examples from other parts of the country where average ranges were much smaller.

Why Indiana foxes need so much room is not settled.

Food and secure cover may be farther apart. Habitat quality may be lower. Foxes could be adjusting their movements around coyotes or other carnivores. Differences in study methods may explain part of the contrast as well. [1]

Still, moving farther has consequences. A fox covering more ground may encounter more roads, more ticks, more competing carnivores and more opportunities to encounter disease.

Then There Is Canine Distemper

Habitat alone cannot explain what researchers found in the dead foxes.

Thirteen radio-marked animals died during the telemetry study. Disease was the largest identified category, accounting for six deaths, or 46%. Two foxes died in vehicle collisions, one was legally harvested, two deaths involved possible poisoning and two remained unexplained. [1]

Indiana DNR’s larger health dataset makes the disease signal harder to ignore.

Genetic material from canine distemper virus was detected in 45 of 85 carcasses tested, or 53%. Canine parvovirus was found in 13 carcasses. Researchers also found exposure to several other pathogens and parasites. [2]

Canine distemper can affect foxes, coyotes, raccoons, skunks and several other carnivores. It does not cause illness in people, but there is no wildlife vaccine program capable of removing the virus from a free-ranging population. [6]

That creates an especially difficult management problem. Restoring cover is something land managers can work on directly. Controlling a virus that circulates among several wild carnivore species is another matter entirely.

Researchers are now looking more closely at whether raccoons, coyotes or other carnivores may act as reservoirs, which distemper strains are circulating and how co-infections affect gray fox survival. [4]

Survival May Not Be the Whole Problem

The study estimated annual survival at 0.61, although the confidence interval was wide because the sample was relatively small. [1]

On its own, that number was not wildly different from survival rates reported in several previous gray fox studies.

Reproduction may be more concerning.

Researchers examining female reproductive tracts estimated a mean of 2.0 placental scars in females one to less than two years old and 3.33 in females two years and older. Five of eight females in the younger adult group showed no evidence of reproduction. [1]

The sample is small, so those numbers should not be treated as a precise statewide birth rate. The authors nevertheless described reproduction as relatively low and noted that reproduction could have a greater influence on the population decline than adult survival.

The Good News Is in the Genes

One obvious concern with a declining animal is whether remaining groups are becoming isolated from one another.

The Indiana genetic results did not show that.

Researchers found relatively good genetic health, low evidence of inbreeding and no clear landscape barrier that explained genetic differences better than simple geographic distance. In other words, Indiana’s remaining foxes do not currently look like a collection of genetically isolated remnants. [1]

There is an important limitation: genetic samples were concentrated heavily in south-central Indiana, so the study had less power to find fine-scale barriers elsewhere in the state.

The authors also noted that Indiana’s agriculture-heavy central region could still create resistance to movement between northern and southern foxes, even though the genetic data did not identify a strong statewide barrier.

For a population already in decline, though, retaining genetic connectivity is one piece of genuinely encouraging news.

What This Means for Southern Indiana

Southern Indiana is not immune to the gray fox decline. Disease was found across the state, mortality occurred among foxes in the study, and the researchers are not claiming that the southern population is secure.

But the region does appear to contain something gray foxes still need.

Crawford, Harrison, Orange and Perry counties contain a much larger share of forest than the central Indiana study site. Public forests, private woodlands, brush, openings and agricultural edges create a more varied patchwork than the broad row-crop country farther north.

The separate statewide distribution model strengthens that interpretation. Its highest probabilities of gray fox presence were associated with forest and combinations of forest, scrub and developed cover rather than the state’s central agricultural core. [3]

That does not mean more fragmentation is the answer. It means habitat arrangement matters.

What Researchers Are Watching Next

Indiana’s gray fox research is not finished.

A second phase began in 2025 and is expected to continue through 2029. According to Indiana DNR, researchers are examining canine distemper strains, other carnivores that may serve as disease reservoirs, co-infections and contaminants including rodenticides. [4]

That work matters because the first phase did something valuable: it narrowed the questions.

Gray foxes are still moving across Indiana. Their genetics do not show a population cut into isolated pieces. Southern Indiana still contains substantial habitat, and the species remains present there.

Yet those foxes are traveling farther than expected, reproducing slowly and encountering a virus that turned up in more than half of the carcasses tested for active infection.

For an animal that is exceptionally good at disappearing into the woods, the warning signs are becoming unusually visible.