Dung beetles roll poop for food, but the ball of dung also serves as a mating gift, a mobile cooling pad, a nursery for larvae, and even a navigational anchor. Some species steer their balls in perfectly straight lines using the Milky Way. Others climb on top and rotate in a deliberate “dance” just to get their bearings. The humble dung ball is one of the most multifunctional objects in the insect world, and the science behind it is stranger than the premise suggests.
What Dung Beetles Actually Eat
Despite hauling around entire balls of the stuff, adult dung beetles do not eat feces the way you might assume. Fresh dung is about 70 to 85 percent water, and the organic solids are mostly fibrous plant material the original animal could not digest. The nutritious part is the microbial biomass living in that material, including bacteria, fungi, and other microorganisms. Adult beetles have soft mouthparts that work like filters, straining out the coarse fiber and extracting the finer, protein-rich microbial particles. They even squeeze excess fluid from this material before swallowing it.1Ecological Entomology. Herbivore dung as food for dung beetles: elementary coprology for entomologists
Larvae are a different story. They have hardened, sclerotized jaws built for chewing coarser material with a higher carbon-to-nitrogen ratio. Their gut microbiomes are enriched in genes for breaking down cellulose and fixing nitrogen, letting them extract nutrition from tougher dung particles that adults cannot handle.2PubMed. Gut microbiota of dung beetles correspond to dietary specializations of adults and larvae This division of labor between adults and larvae means the same pile of dung can feed two entirely different digestive strategies at two life stages.
Finding the Right Dung in the First Place
A fresh pile of elephant or cattle dung does not sit around for long on a warm savanna. Dozens to hundreds of beetles may arrive within minutes, and different species show strong preferences for particular types of dung. The way they locate and choose dung is olfactory: their antennae respond to volatile compounds wafting from the pile. Research using electroantennogram recordings found that all 19 tested dung-associated compounds triggered antennal responses in dung beetles, but species with different dietary preferences showed distinct olfactory profiles. A specific subset of compounds, including indole, p-cresol, and nonanal, were the strongest drivers separating species that preferred one dung type over another.3PubMed Central. Links Between Feeding Preferences and Electroantennogram Response Profiles in Dung Beetles: The Importance of Dung Odor Bouquets In other words, what smells terrible to us is a carefully parsed chemical landscape for a beetle homing in on its preferred meal.
Rolling as a Mating Strategy
For many roller species, sculpting and moving a dung ball is not just about securing food. It is courtship. Males typically arrive at the dung pat first, cut out a portion, shape it into a ball, and begin rolling it away. While doing so, they release pheromones from specialized glands to attract females. If a female is interested, she climbs aboard the rolling ball and rides it, or follows behind as the male pushes it to a suitable burial site.4Elsevier. Plasticity in sex roles and female competition in Neotropical dung roller beetles The size of the ball, the speed and competence of the roll, and the male’s ability to fend off rivals all factor into whether he successfully pairs up.
Competition can be fierce. Other males may try to steal the ball outright. Females also compete with each other for access to males and their dung balls, because the ball’s quality directly determines breeding success. Once a pair reaches a soft patch of ground, they bury the ball and the female reshapes portions of it into brood balls, each containing a single egg. The interior of the brood chamber is lined with a smooth secretion matrix that harbors specific rod-shaped microbes, sandwiched against the chamber walls. These microbes are absent from the rest of the brood ball, suggesting the mother deliberately inoculates the egg chamber to seed her offspring’s gut microbiome.5PLOS ONE. Brood Ball-Mediated Transmission of Microbiome Members in the Dung Beetle, Onthophagus taurus (Coleoptera: Scarabaeidae)
The Dung Ball as Air Conditioning
On the baking sands of the Kalahari and similar environments, soil surface temperatures can exceed 60°C. For a small beetle pushing a ball backwards with its hind legs, this presents a serious overheating problem. A wet dung ball, though, is substantially cooler than the surrounding sand because of evaporative cooling. Researchers measuring ball temperatures with infrared thermography found that moist dung balls sat around 32°C while the surrounding soil and the beetle’s own body were much hotter.6Current Biology. Dung beetles use their dung ball as a mobile thermal refuge
Beetles exploit this by periodically climbing on top of their ball, pressing their body and legs against the cooler surface. When researchers gave beetles a choice between rolling a pre-cooled ball and a pre-heated ball across a hot arena, the beetles climbed the hot ball about 73 percent more often than the cold one. That seems counterintuitive until you consider that a hot ball is less effective as a heat sink, so the beetle needs to cool off more frequently but gets less relief each time. With a cool ball, the beetle’s feet stay cooler during rolling and it needs fewer breaks. The dung ball, in short, is a portable air-conditioning unit.7PubMed. Dung beetles use their dung ball as a mobile thermal refuge
Navigating by the Milky Way, Moon, and Sun
Once a beetle has shaped its ball at a crowded dung pat, its single most urgent task is to get away fast, in a straight line, before another beetle steals its prize. Wandering in circles would bring it right back to the competition. To avoid that, dung beetles have evolved some of the most remarkable navigation systems in the insect world, and they differ depending on whether the beetle is active during the day or at night.
Daytime Rollers
Day-active species use a combination of the sun’s position and the pattern of polarized light in the sky. When researchers blocked the sun but left the sky visible, beetles could still orient in a straight line using the polarization pattern alone. Rotating the apparent direction of polarization with a filter shifted the beetles’ rolling direction by a corresponding angle.8Journal of Experimental Biology. Diurnal dung beetles use the intensity gradient and the polarization pattern of the sky for orientation The sun and the polarization pattern work together, but the sun’s usefulness drops around midday. At solar elevations above 75 degrees (close to directly overhead), orientation error roughly doubled compared to when the sun was lower in the sky.9PubMed Central. The role of the sun in the celestial compass of dung beetles A midday sun is poor compass material because it moves little across the sky, leaving the beetle more reliant on polarized light gradients.
Moonlit Rollers
Nocturnal species face a dimmer challenge. One species, Scarabaeus zambesianus, was the first insect shown to orient using the polarization pattern of moonlit sky, a signal roughly a million times fainter than its daytime equivalent. Researchers found that hiding the moon’s disc barely affected the beetles’ orientation, but disrupting the broad polarization pattern around the moon threw them off, confirming that the polarization field, not the moon itself, is the primary cue.10PubMed Central. Lunar orientation in a beetle These beetles can detect degrees of polarization as low as about 0.04 to 0.32, a sensitivity range comparable to what daytime insects achieve.11PubMed. Orienting to polarized light at night – matching lunar skylight to performance in a nocturnal beetle
Starlight Rollers
The most celebrated finding came from a species called Scarabaeus satyrus, which rolls on moonless nights. Under a clear starlit sky, these beetles maintain impressively straight paths. Under overcast skies, they wander. In a planetarium, researchers showed that the beetles orient just as well when only the Milky Way is projected as when the full starry sky is displayed. That made them the first animals ever documented using the Milky Way for navigation.12PubMed. Dung beetles use the Milky Way for orientation Follow-up work revealed the mechanism is not star-pattern recognition, as birds and seals are thought to use, but something cruder and more effective for a tiny brain: comparing the brightness of different regions of the Milky Way’s band. This intensity-comparison strategy is robust to seasonal changes in which stars are visible and to mild atmospheric haze.13PubMed Central. Stellar performance: mechanisms underlying Milky Way orientation in dung beetles
The Dance on Top of the Ball
Anyone who has watched dung beetles in the field, or in a nature documentary, has probably noticed the peculiar behavior of a beetle climbing on top of its ball and rotating in place before rolling again. This is not random. Research on the diurnal species Scarabaeus nigroaeneus found that the dance is triggered whenever the beetle loses control of the ball, loses contact with it, or gets knocked off course. Experimentally changing the visual cues around the beetle also triggered the dance. The rotating behavior lets the beetle take a fresh “snapshot” of the sky, essentially recalibrating its compass bearing before continuing its straight-line escape from the dung pat.14PLOS ONE. The Dung Beetle Dance: An Orientation Behaviour?
The dance serves double duty with the thermoregulation function described earlier. On hot ground, a beetle that climbs the ball to recalibrate its celestial compass is also pressing its overheated legs against a cooler surface. Whether these two functions evolved together or one piggybacked on the other is still debated, but the result is a single behavior that solves two problems at once.
How Rolling Actually Works, Mechanically
Watching a beetle push a dung ball that may outweigh it several times over looks effortless from a distance, but the biomechanics are unusual. The beetle stands on its front legs and pushes backward, with the ball held between its hind and middle legs. The front legs generate forward thrust against the ground in a motion similar to walking backward, while the middle and hind legs step on the ball’s surface in the opposite rotational direction, essentially walking forward on the ball to keep it spinning.15PubMed Central. Rules for the Leg Coordination of Dung Beetle Ball Rolling Behaviour This coordinated counter-rotation between the ground-pushing front legs and the ball-gripping rear legs is mechanically distinct from any standard insect walking gait. Roller species tend to have distinctively elongated hind tibiae compared to tunnelling species, a morphological signature so consistent that it can separate the two lifestyles in shape analyses across four different biogeographic regions.16Journal of Biogeography. Local and regional ecological morphology of dung beetle assemblages across four biogeographic regions
What Dung Beetles Do for the Landscape
The sheer volume of dung processed by beetles translates into substantial benefits for the ecosystems they inhabit. A meta-analysis of 24 studies found that dung beetle activity increased plant growth by roughly 17 percent on average. The effect scaled steeply with beetle numbers: when about 100 beetles worked a site rather than 10, plant growth increased by about 75 percent.17Proceedings of the Royal Society B: Biological Sciences. Dung beetles increase plant growth: a meta-analysis This happens because burying dung incorporates nutrients directly into the root zone, aerates the soil, and reduces surface crusting that would otherwise block water infiltration.
Beetles also move seeds. Many plants depend on animals eating their fruit and depositing seeds in dung. But a pile of seeds sitting on the surface in a clump of feces is a poor start; seeds that stay on top are vulnerable to predators and disease, and crowded seedlings compete with each other. Dung beetles are the main agents that break apart these fecal deposits and move the seeds, both horizontally (rolling or dragging dung away) and vertically (burying it underground). In one study of brown bear feces in a temperate mountain ecosystem, dung beetles were the primary agents of feces removal and secondary seed dispersal, with rodents playing no measurable role.18Ecosphere. Dung beetles, but not rodents, contribute to brown bear feces removal, disaggregation, and secondary seed dispersal Other research confirmed that beetle-mediated dispersal reduces seed and seedling clumping, though short-term seedling establishment was not necessarily improved.19PubMed Central. Horizontal seed dispersal by dung beetles reduced seed and seedling clumping, but did not increase short-term seedling establishment
There is a less glamorous benefit, too. By breaking apart and burying dung pats, beetles disrupt the life cycle of livestock gastrointestinal parasites, whose eggs and larvae develop in surface dung before being ingested by grazing animals. Research on temperate pastures showed that dung beetle communities reduce the development and survival of these parasitic stages over a grazing season, making beetle conservation relevant to livestock health management as well as ecology.20Journal of Applied Ecology. Dung beetles reduce livestock gastrointestinal parasite availability on pasture
The Ivermectin Problem
The irony of the parasite-control benefit is that one of the most widely used livestock deworming drugs, ivermectin, is devastating to the beetles that would otherwise suppress those same parasites naturally. Ivermectin passes through treated livestock and persists in their dung for weeks. Beetles that colonize treated dung suffer reduced mobility, loss of coordination, and death at even relatively low doses.21Scientific Reports. Low doses of ivermectin cause sensory and locomotor disorders in dung beetles Sublethal exposure is arguably worse in the long run: it disrupts ovary development, stops egg maturation, and sharply reduces fecundity. Larvae are even more sensitive than adults. After cattle receive a standard recommended dose, ivermectin concentrations in their dung during the first two weeks far exceed the thresholds shown to harm beetle reproduction and kill larvae.22The Canadian Entomologist. The effects of sublethal and lethal doses of ivermectin on the reproductive physiology and larval development of the dung beetle Euoniticellus intermedius
At the population level, the consequences are measurable. Pastures where ivermectin is routinely used had about 35 percent fewer beetle species and 44 percent fewer individual beetles per dung pat. The species hit hardest were those that contribute most to dung removal, the tunnellers and dwellers that bury and process dung, while species whose larvae feed on other things were unaffected. This selective loss of the most functionally important beetles reduced the overall dung-removal capacity of the community, and the effects persisted well beyond the period when the drug was physically present in the system.23Agriculture, Ecosystems & Environment. Lasting decrease in functionality and richness: Effects of ivermectin use on dung beetle communities Farmers using ivermectin to control parasites may inadvertently be weakening the natural pest-suppression service that healthy beetle communities provide for free.
The Sacred Scarab and Why Ancient Egyptians Noticed
Humans have been watching dung beetles roll balls for a long time. Ancient Egyptians were captivated by Scarabaeus sacer, the species whose ball-rolling behavior inspired one of the most enduring symbols in their religious art. The scarab beetle appeared in tomb hieroglyphics, drawings, amulets, and hand-carved figurines buried with the dead. Egyptians associated the beetle’s ball-rolling with the movement of the sun across the sky, linking it to the god Khepri, who was said to push the sun from east to west each day. These beliefs can be traced back at least to the pyramid-building era, around 2500 BCE, and were probably already ancient at that point.24Oxford Academic (American Entomologist). Insects as Sacred Symbols in Ancient Egypt The metaphor made intuitive sense: a beetle painstakingly rolling a sphere of earth across the ground looked like a small god sustaining the cosmos. It is a surprisingly apt metaphor, given what we now know about the ecological weight these insects actually carry.