TEXAS HOG DISPATCHTHE TRACKER · THE MOONLIGHT LAB
Tracker
The Moonlight Lab

The Moon Is Not the Forecast

Does the full moon change feral hog activity? Ten studies, three layers of certainty, and no forecast.

Evidence explainer with interactive comparisonsResearch updated

Short answer

Moonlight can influence feral hog activity, but research has not found one universal response. Some studied populations became less active during brighter conditions, others became more active, and several studies found little, no, or conditional effects. Habitat, weather, hunting pressure, predators, season, artificial light, and the way moonlight was measured are all possible reasons the studies disagree.

Moon phase is easy to calculate. Moonlight is harder. Wild-hog behavior is harder still.

1. Astronomical facts

Lunar phase and illuminated fraction, calculated. Position, rise, and set only when actually computed.

2. Estimated light context

Outdoor light shaped by Moon geometry, clouds, canopy and cover, terrain, and artificial light.

3. Hogs

Property-specific behavior cannot be forecast from moon phase alone. This page produces no activity score.

The Moon Did Not Change. The Night Did.

Move the slider. The illuminated fraction stays the same all night, yet the pasture, the creek bottom, and the suburban edge are three different nights. Switch to overcast and notice that the open field goes dark while the lit-up neighborhood can get brighter, because clouds reflect skyglow back down.

Open pastureWooded creek bottomSuburban edge
Sky

Illuminated fraction: calculating… — unchanged by the sliderMoon position and sky: conceptual, not a local calculation

Conceptual visualization. The phase and illuminated fraction come from the Tracker's existing lunar calculation. Moon altitude, rise and set times, cloud cover, and ground light are illustrated assumptions, not measurements for any location.

Reveal: the Moon did not change. The night did.

Phase Is Not Moonlight

The illuminated fraction, the number you see on the Tracker's Moon card, describes how much of the Moon's face is lit as seen from Earth. NASA's Scientific Visualization Studio publishes the phase and libration cycle for each year, and JPL's Horizons system can compute where the Moon sits in the sky for any place and time. Those are astronomy facts, and they are the only thing NASA and JPL sources establish on this page.

Light reaching the ground is a different quantity. It depends on how high the Moon is, how long it is above the horizon, whether clouds or haze sit in between, how much canopy and terrain shade a given spot, and how much artificial light is already there. Brightness does not scale in a simple straight line with the illuminated percentage, and none of that is measured for your property by any tool here. This release does not make live JPL or API calls; it uses the Tracker's existing phase calculation only.

What the Studies Actually Found

Filter by finding, open a card, and follow the link to the original paper. The disagreement is the point; it is shown here rather than averaged away.

Showing 10 of 10 studies.

Central Italy · Less active when brighterGordigiani et al. 2022
Location
Central Italy
Method / sample
Camera traps; 1,048 wild boar records.
Finding
Activity declined under the brightest measured conditions. A composite sky-brightness measure that combined phase with visibility and cloud conditions explained activity better than calendar phase alone.
Context
Mixed oak woodland with wolves present and ongoing hunting and poaching.
Limitation
One region; camera detections stand in for activity.
Source
Gordigiani et al. (2022). Mammal Research.
Italy · More active when brighterBrivio et al. 2017
Location
Italy
Method / sample
GPS collars with accelerometers measuring activity.
Finding
Temperature, precipitation, and humidity were significant. In this population, nocturnal activity increased slightly as moonlight increased.
Context
A weather-driven activity pattern with a small, positive moonlight term.
Limitation
One population; the moonlight effect was small relative to weather.
Source
Brivio et al. (2017). Mammalian Biology.
Germany · Little or no effect foundJohann et al. 2020
Location
Germany
Method / sample
46 GPS-tracked wild boar; 6,716 daily ranges.
Finding
Moon brightness was not statistically significant for daily range size.
Context
Movement (range size), not activity or detection, was the measured outcome.
Limitation
Cloudiness was not included in the model.
Source
Johann et al. (2020). Wildlife Biology.
Southern Italy · Less active when brighterGaudiano et al. 2022
Location
Southern Italy
Method / sample
Field study of wild boar activity across lunar conditions.
Finding
Greater activity during the darkest nights and lower activity around full moon in that ecological setting.
Context
Wolves and predation risk may be part of why darker nights were used more.
Limitation
Setting-specific; the risk context is not the same everywhere.
Source
Gaudiano et al. (2022). Mammal Research.
Elba Island, Italy · Little or no effect foundFedele et al. 2022
Location
Elba Island, Italy
Method / sample
One-year study of wild boar activity by season.
Finding
No moon-phase effect was detected in any season.
Context
An island population with its own predator and hunting context.
Limitation
A single year limits what can be inferred.
Source
Fedele et al. (2022). Mammalian Biology.
Northern China · Less active when brighterZaman et al. 2022
Location
Northern China
Method / sample
102 cameras; 4,599 trap nights; 414 wild boar events.
Finding
Lower activity around brighter and full-moon conditions, with a significant interaction with cloud cover.
Context
Leopards and people were part of the landscape.
Limitation
Camera detections; one mountain region.
Source
Zaman et al. (2022). Ecology and Evolution.
South Carolina, United States · Conditional effectSaldo et al. 2023
Location
South Carolina, United States
Method / sample
Camera detections of wild pigs by season.
Finding
A positive moon-phase effect on detection appeared only in winter.
Context
The closest study here to Texas conditions, but still a different state and habitat.
Limitation
Fewer than 50 detections in each season; detection is not total activity.
Source
Saldo et al. (2023). Ecosphere.
Mediterranean sites · Conditional effectLazzeri et al. 2025
Location
Mediterranean sites
Method / sample
Multi-site comparison of wild boar activity.
Finding
No general overall moon effect. Brighter-night activity appeared specifically at sites heavily used by wolves.
Context
The moon effect depended on the predator context of each site.
Limitation
Site-level differences drive the result; it is not a single direction.
Source
Lazzeri et al. (2025). Journal of Zoology.
Southern United States (six states) · Context only (not a moon test)Kay et al. 2017
Location
Southern United States (six states)
Method / sample
400,000+ GPS locations from 226 wild pigs across 13 studies.
Finding
Movement varied with temperature, barometric pressure, water, ecoregion, sex and age, and the scale of measurement.
Context
This study did not test moonlight. It is context on what else drives movement, not moon-effect evidence.
Limitation
Not a moon study; do not read it as one.
Source
Kay et al. (2017). Movement Ecology.
Meta-analysis · Context only (not a moon test)Prugh and Golden 2014
Location
Meta-analysis
Method / sample
58 studies covering 59 nocturnal mammal species.
Finding
Moonlight responses varied with vision, habitat cover, and phylogeny.
Context
A cross-species pattern, not a hog-specific result.
Limitation
Not hog-specific; it frames why responses differ rather than what hogs do.
Source
Prugh and Golden (2014). Journal of Animal Ecology.

Why the Studies Disagree

  1. Habitat. Woodland floors stay dim on bright nights; open ground does not. The cross-species meta-analysis by Prugh and Golden found habitat cover shaped moonlight responses.
  2. Methods. Camera detections, GPS range size, and accelerometer activity measure different things. A camera can record fewer detections while animals are just as active elsewhere.
  3. Weather. Temperature, rain, and humidity dominated the Italian GPS study; heat and water matter across the southern U.S. GPS dataset, which never tested moonlight.
  4. Predators. Wolves in Italy, leopards in China. Lazzeri et al. found brighter-night activity specifically at wolf-heavy sites. Texas has neither, so "lunar phobia" should not be treated as settled or as automatically applicable here.
  5. People. Hunting and poaching pressure differed across every study.
  6. Season. The South Carolina effect appeared only in winter; Elba showed none in any season.
  7. Clouds and how moonlight was measured. Studies that folded cloud or sky brightness into the model (Gordigiani, Zaman) explained more than calendar phase alone; the German study did not include cloudiness at all.
  8. Artificial light. None of these studies measured a Texas suburb. Near skyglow, clouds are not simply a dimmer.

Move the Study

Choose one real study and one Texas landscape. The result is a transparent list of what stays comparable, what changed, and what evidence would be needed here. It never produces a similarity percentage or a Texas behavior prediction.

Gordigiani et al. 2022 (Central Italy) moved to a Texas open cattle pasture. Categories only — no similarity score and no prediction.

What remains comparable

  • Same species: Sus scrofa (wild boar and feral hogs are the same species).
  • Same Moon, same phase cycle, same geometry of moonlight.

What changed materially

  • Cover: the study site was mixed oak woodland (heavy cover); this landscape is open ground. Cover changes how much moonlight reaches the ground and how exposed an animal feels.
  • Predators: the study context was "wolves present." Texas has no wolf or leopard populations; the risk context is different, and several studies point to predators as part of why moon responses differ.
  • Climate and season: Mediterranean, temperate there versus Texas heat, drought cycles, and water availability here.
  • People: hunting and poaching pressure there; livestock work, feeding routines, occasional night traffic here.

What may transfer

  • The method lesson: measure sky brightness or cloud cover together with phase. Calendar phase alone explained less in this study.
  • The design lesson: camera detections need bait status and site notes because detection is not the same as movement or abundance.
  • A testable question for local cameras, not an answer.

What should not be transferred

  • The direction of the finding ("Less active when brighter") as a prediction for this property.
  • Any size or timing of the effect. No study here was done in Texas.
  • Detection counts as if they were total activity or abundance.

Local evidence that would be needed

  • Timestamped camera or GPS records from this property across a full year.
  • Nightly sky notes (cloud cover, haze) recorded alongside phase, not phase alone.
  • Bait status, trapping and hunting activity, and other disturbance logged night by night.

Same Moon, Five Properties

The same illuminated fraction lands very differently on the ground.

Open cattle pasture

Exposure: Wide-open sky; moonlight reaches the ground with little in the way.

Sightlines: Long sightlines for animals and for people.

Cover: Little cover beyond fence lines and scattered trees.

Artificial light: Usually low artificial light, apart from a yard light or barn.

Human activity: Livestock work, feeding routines, occasional night traffic.

Agricultural field

Exposure: Open until the crop stands tall; exposure changes with the season.

Sightlines: Long across the field, short inside a mature crop.

Cover: Crop rows can become cover for part of the year.

Artificial light: Generally low, though equipment and roads can add light.

Human activity: Planting, harvest, and irrigation schedules change disturbance.

Wooded creek bottom

Exposure: Canopy blocks much of the sky; the ground stays dim on any night.

Sightlines: Short and broken by trunks, brush, and terrain.

Cover: Dense cover, water, and wallows close together.

Artificial light: Usually very low artificial light.

Human activity: Less foot traffic; hunting and trapping pressure varies by property.

Dense brush

Exposure: Low sky exposure at ground level under mesquite, cedar, and thicket.

Sightlines: Very short.

Cover: Heavy cover in every direction.

Artificial light: Typically low.

Human activity: Varies with ranch operations and lease hunting.

Suburban greenbelt

Exposure: Mixed: open lawns and trails next to shaded corridors.

Sightlines: Broken by fences, structures, and vegetation.

Cover: Strips of cover along creeks and drainage easements.

Artificial light: Streetlights, porch lights, and skyglow are present every night.

Human activity: High human activity, pets, traffic, and restrictions on hunting.

What Moonlight Research Means for Texas Landowners

Drought and water. The large southern U.S. GPS dataset tied movement to water and temperature, not moonlight. In a Texas drought, where water sits likely matters more than what the Moon is doing.

Heat and rain. Weather terms carried the Italian GPS model. Texas summers push activity into cooler hours regardless of phase.

Hunting and trapping pressure. Every study site had its own pressure history, and pressure changes behavior. See the Catchability Gap for how pressure shapes what remains.

Rural versus suburban. No cited study measured a lit suburban greenbelt. The artificial-light layer is an open question, not a known.

No property-level light measurements. Nothing here measures the light on your ground. This page offers no guidance about when to hunt or trap, and moon phase should not be read as that guidance.

Known, Estimated, Unknown

Known

Calculated from the Tracker's existing lunar utility for today's date.

  • Phase: calculated after page load
  • Illuminated fraction: calculated after page load
  • Altitude, azimuth, rise, transit, and set: not calculated in this release, so they are not listed as known.

Estimated

Outdoor light context, based on stated assumptions rather than measurement.

  • Moon geometry through the night (illustrated, not computed for a location).
  • Cloud, canopy, and terrain effects on ground light.
  • Artificial light and skyglow in built-up areas.

Unknown

What no calculation on this page can supply.

  • How hogs on a specific property respond to tonight's conditions.
  • Whether any study's direction applies here without local observations.
  • Actual ground illumination at any Texas site.

Questions people ask

Does the full moon make feral hogs less active?

Not universally. Several studies in Italy and northern China found lower activity under brighter conditions, one Italian GPS study found a slight increase, and studies in Germany and on Elba Island found no significant moon effect. A South Carolina study found a positive moon-phase effect on camera detections only in winter.

Is the illuminated percentage the same as how bright the night is?

No. The illuminated fraction describes how much of the Moon's face is lit. Light on the ground also depends on where the Moon is in the sky, clouds, canopy and terrain, and artificial light. This page does not measure ground illumination.

Can moon phase predict hog activity on my property?

No. The studies disagree, none of them were done in Texas, and property-level behavior depends on local habitat, weather, pressure, and disturbance. This page does not produce a hog activity score or forecast.

Is there a Texas study on moonlight and feral hogs?

None is cited here. The large southern U.S. GPS study by Kay et al. (2017) covered six states but did not test moonlight, so it is context rather than moon-effect evidence.

Original studies and sources

Wild boar and feral hog studies

Astronomy (Moon facts, not hog behavior)