The Social Function of Latrines: A Hypothesis-Driven Research Approach

Abstract

In many mammals, the function of latrine use is still debated. Suggested explanations can be broadly divided into resource defence, information centre/ advertisement, landmarks/ orientation, parasite control, or predator-prey interactions. Here, we develop a hypothesis-driven research framework based on the six categories of data that can be collected from latrines (spatial distribution patterns of latrines; temporal usage patterns of latrines; visit and contribution patterns of individual animals to individual latrines; behaviour of visitors to and/ or users of latrines; the longevity, volatility and lifespan of the scent signals) to help investigate the role of latrine use in any focal species. We emphasise that, due to the complexity of the information content encoded in olfactory signals, in most mammals latrine use is likely multi-functional.

Vicuña dung gardens at the edge of the cryosphere

“…Creation of latrines is ubiquitous in mammals (Eisenberg and Kleiman 1972, Brown and Macdonald 1985, Gorman and Trowbridge 1989), and latrines are hypothesized to function primarily as information centers that transfer social information between individuals and groups such as identity, health, social status, location information, and home range or territory boundaries (Buesching and Jordan 2019). Alternative hypotheses for latrine behaviors include avoidance of parasite transmission and predator avoidance (Hart 1994, Boonstra et al 1996, Buesching and Jordan 2019). Alpacas, domesticated relatives of vicuñas, have been observed grazing at their latrine sites when forage was limited during the dry season (McGregor and Brown 2010).…”

Knowing Me, Knowing You: Anal Gland Secretion of European Badgers (Meles meles) Codes for Individuality, Sex and Social Group Membership

“…Thus, many carnivores advertise ownership of essential resources as a pre-emptive measure to avoid conflict (Buesching and Stankowich 2017). This is achieved most efficiently with low-maintenance long-term signals that do not require the continual physical presence of the owner (Buesching and Jordan 2019), but that can be matched to the marking individual (the scent-matching hypothesis Gosling 1986). Inter-group differences in odor profiles were clearly apparent in our badger AGS data, reflecting results from a similar study analyzing the composition of subcaudal gland secretions in this same badger population (Buesching et al 2002).…”

“…Crucially, however, much of the information content in VOCs is temporary. In order to maximize their functionality, territorial scent-marks, which in any non-solitary species need to also include groupmembership information, are expected to be long-lasting in the environment (Buesching and Jordan 2019). Because cue longevity is achieved predominantly by non-volatile compounds, we posit that similar, if not more pronounced, intergroup differences should be apparent in the relative abundance of longer-lived, non-volatile compounds as described in Davies et al (1988).…”

“…According to the 'social complexity hypothesis' (reviewed in Freeberg et al 2012), group-living also places evolutionary pressure on complex communication systems, selecting for increasingly complex individual-specific signals (Pollard and Blumstein 2011). The potential for each individual of a species to have its own olfactory "fingerprint" (Müller-Schwarze 2009) is particularly important in all group-living species that rely on olfactory communication to maintain stable sociospatial networks (Buesching and Jordan 2019). In badgers, because all members of several neighboring social groups use the same latrines, encoding information pertaining to individuality and group-membership in feces and/or AGS is a prerequisite for any individual level advertisement (Buesching and Jordan 2019;Buesching and Macdonald 2001;Buesching and Stankowich 2017), where here we evidence that Because the ability to find and attract members of the opposite sex as potential mates as well as to identify potential same-sex rivals is crucial for all sexually reproducing species, the ability to encode sex is likely fundamental to advertisement signals (Johnston and DelBarco-Trillo 2009).…”

Measuring Salivary Cortisol in Wild Carnivores

“…Finally, because animals excrete on their own schedule and in their preferred locations, feces and urine can be difficult to collect. For instance, carnivores defecate infrequently compared to herbivores, and many animals defecate in latrine sites, where previously deposited feces might contaminate new samples (Buesching and Jordan, 2019). Urine can be especially difficult to collect as it quickly disperses or is absorbed by the substrate (Danish et al, 2015).…”