The research team set up digital camera traps along forest trails during the rainy season between October 2016 and February 2017, recording 10-second videos around the clock without bait. Four sampling points were monitored across the protected areas of the block, which covers roughly 53,000 hectares and represents the largest remnant of native vegetation in Espírito Santo. Although deer were recorded at all four points, latrine use was confirmed at only two of them, where 25 interactions with the latrines were documented alongside 27 independent records of the species, totaling 29 specimens.

Five distinct behaviors emerged from the video analysis: defecation, urination, front paw scratching against the ground, tail shaking, and sniffing the area near the latrine. Sniffing was the most common behavior, accounting for 40 percent of records, followed by defecating and urinating at 20 percent each, with ground scratching at 12 percent and tail shaking at 8 percent. Remarkably, females performed 56 percent of the recorded behaviors, males 40 percent, and specimens of undetermined sex the remaining 4 percent—a reversal of what might be expected in a species where males are often assumed to be the primary territory markers.

The chemical messages deposited at latrines serve as a kind of biological bulletin board. Because scent signals persist at a location even when the depositing individual is absent, latrines allow deer to communicate identity, sex, and potentially reproductive status across time. The species possesses well-developed sebaceous and sudoriferous glands in the orbital, frontal, and interdigital regions, as well as highly developed glands associated with the tail, all of which likely contribute pheromones to the signaling system. When deer defecate or urinate, they squat with the tail fully raised, exposing the white underside of the tail—possibly another source of chemical cues.

The temporal patterns captured in the study add another layer of intrigue. The interval between odoriferous marking records at the same latrine ranged from less than 24 hours to more than a month, and marking occurred during all periods of the day—morning, afternoon, and night. However, ground scratching was never documented at night, suggesting that this more elaborate behavior may be reserved for daylight hours when visual and chemical signals can reinforce each other. The variation in marking frequency between the two latrines also hints that different sites may serve different roles within the same population.

Sex-based differences in latrine use were among the most striking findings. At one latrine, females contributed more frequently to maintenance, with urine deposition performed mainly by females, while at the other latrine, only males were confirmed to deposit feces and urine or perform ground scratching. This intersexual variation suggests that males and females may employ distinct territorial marking strategies. Prior research indicates that male gray brocket deer more frequently mark outside and at the boundary of their territories, while females mark within their home ranges, defending central areas as small territories.

The communication function of latrines likely extends beyond simple territory defense. Both males and females recognize their own aromatic marks, while the scent of unfamiliar individuals triggers investigative sniffing. The detection of feces or urine from other individuals of the same sex induces over-marking—defecation and urination in the same latrine or nearby—serving to reaffirm presence in what may be a response to intrasexual competition. Meanwhile, encounters between individuals of the same sex may trigger aggression, whereas encounters with the opposite sex elicit receptive behavior, making latrines a potential mechanism for preventing unwanted agonistic interactions.

The reproductive dimension of latrine use may be equally important. Females can potentially assess a male’s health status and genetic quality through chemical cues, and reproductive periods tend to show higher accumulation of feces at specific sites as part of sexual communication strategy. The fact that a female and a male were recorded together or within minutes of each other at the latrines in this study reinforces the possibility that latrine use is associated with reproductive communication. In related species such as rhinoceroses, urine carries the estrus signal of females, and it is plausible that intensified urine marking by female gray brocket deer during the sampling period coincided with estrus.

Understanding these latrine behaviors has practical implications for conservation. As habitat fragmentation continues to isolate populations of Neotropical mammals, decoding the chemical communication strategies of species like the gray brocket deer becomes essential for designing effective monitoring programs. Latrines could serve as monitoring stations, allowing researchers to detect presence, estimate abundance, and even gauge reproductive activity without capturing or disturbing the animals. The study’s findings, though limited to a few sampling points, highlight the complexity of territorial marking behavior in this species and underscore how much remains to be discovered about the secret lives of Neotropical deer.

Subject of Research: Chemical communication and latrine use by gray brocket deer in the Atlantic Forest

Article Title: Use of latrines and territorial marking behaviors by Subulo gouazoubira in a remnant of the Atlantic Forest in southeastern Brazil

Article References: Srbek-Araujo, A. C., & Alzuguir, L. D. C. (2024). Use of latrines and territorial marking behaviors by Subulo gouazoubira in a remnant of the Atlantic Forest in southeastern Brazil. Neotropical Biology and Conservation, 19(3), 367-378. https://doi.org/10.3897/neotropical.19.e121917

Image Credits: AI Generated

DOI: 10.3897/neotropical.19.e121917

Keywords: gray brocket deer, Subulo gouazoubira, Atlantic Forest, latrines, chemical communication, territorial marking, camera traps, wildlife behavior, Brazil, conservation, territorial, marking