Dung middens, also known as dung hills, are piles of dung that mammals periodically return to and build up. They are used as a form of territorial marker. A range of animals are known to use them including steenbok, hyrax (the dung beetle genus Dicranocara of the Richtersveld in South western Africa spends its whole lifecycle in close association with hyrax dung middens) and rhinoceros. Other animals such as beetles are attracted to them for a variety of purposes. This can include food as well as a location to find a mate. Dung often contains pollen which means fossilised dung middens can be used to learn about past climates. Paleobotany relies on the fact that each ecosystem is characterised by certain plants, which in turn act as a proxy for climate.
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Climate Information
Pollen that becomes fossilized in dung midden can provide information about the climate and environment during that time period.
Namib Desert
Much is unknown about the origins of the unique biodiversity in the Namib desert. It has an arid climate and granitic substrate, which does not favor the preservation of organic material that would typically help provide insight into the history of the biodiversity.
Hippopotamus
Dung middens as a social tool in the common hippopotamus has been a known phenomena for decades. The middens are created and maintained by male bulls to mark territorial boundaries. To mark their scent upon a midden, the bull will approach the midden in reverse and simultaneously defecate and urinate on the mound, using its tail to paddle the excrement. This action is called dung showering and thought to assert dominance. The middens are constantly maintained during the bulls travels during the night and day.
Rhinoceros
The behavior is also observed in the White and Black rhinoceroses. The middens are shown to provide cues as to the age, sex, and reproductive health of the producer. Some of the middens can be 65 feet across. Dung beetles are frequently found in these middens and lay their eggs within the mounds. Their presence and activity in the middens also aid in pest and parasite control. Unlike the hippopotamus, rhino dung middens are shared.
White rhino middens are marked by a black color and a primarily grass composition whereas black rhino middens tend to be brown and contain more twigs and branches. In addition to dung middens, black rhinos may mark their territory by rubbing their heads, which have pungent skin glands, on trees or other landmarks.
Black Garden Ants
Midden formation in insects was first observed in Black Garden Ants, Lasius niger. The middens created by the ants are called "kitchen middens" and are composed of food scraps, ant corpses, and other detritus. A reason for the behavior has yet to be determined though it may possibly serve as a feeding ground for larvae.
Lemurs
The Dry Bush Weasel Lemur and Southern Gentle Lemur are known to construct middens. It is thought that these act primarily as communal latrines and communication tools for families spread over large tracts of land.
Ecological Implications
The widespread presence of dung midden use throughout the animal kingdom is coupled with a distinct variation in how dung middens are used from species to species. Dung midden use has been implicated in the context of both intraspecific markers of territory, sexual availability, and a part of antiparasite behavior, but also as an essential part of the ecosystem, with interspecies interactions between the creators and users of dung midden piles.