Ring‐tailed lemurs (Lemur catta) use olfaction to locate distant fruit

Abstract

Objectives As many primates live in forests where visibility is limited, the ability to detect the aroma of distant fruit and navigate odor plumes would be highly adaptive. Our study is the first to investigate this ability with strepsirrhine primates. Materials and Methods We tested the ability of a group of ring‐tailed lemurs to detect hidden fruit from afar using scent alone. We hid containers in the underbrush of a semi‐natural forest, some baited with real cantaloupe and some with sham cantaloupe, 4–17 m from a path routinely used by the lemurs. Crucially, the containers were not visible from the path. Therefore, the lemurs had to use olfactory cues, but did not have to prioritize them to locate the bait. Results The lemurs found the real cantaloupe on days that the wind blew the scent of the fruit toward the trail. They did not find the sham cantaloupe. Upon detecting the odor of the bait, the lemurs sniffed the air at one or more locations as they moved toward the bait, a process of navigation known as klinotaxis. Discussion The traditional belief is that primates are unable to track odor plumes. The untrained lemurs in this study were able to detect the odor of the cantaloupe among the complex odors of the forest and navigate the odor plume to the fruit. The results indicate that olfaction may be used to respond to cues from distant sources. The ability to track odor plumes may be a critical foraging skill for strepsirrhines.

Fruit scent as an honest signal for fruit quality

“…The main consumers of F. tiliifolia are lemurs, and as primates they are more likely to use spatial knowledge of their habitat to locate fruiting trees while using olfaction primarily for quality assessment of individual fruits once in the tree [ 43 ]. While long-distance use of olfaction to find fruit has been experimentally demonstrated in lemurs [ 44 ], it is unlikely, although not impossible, that the subtle differences between trees here would be useful for fruit-foraging consumers. This implies that within tree variation is ecologically much more relevant, allowing consumers to quickly assess whether an individual fruit should be ingested or not.…”

The sensory ecology of primate food perception, revisited

“…Squirrel monkeys ( Saimiri sciureus ) and pig‐tailed macaques ( Macaca nemestrina ), for example, are sensitive to extremely low concentrations of fruit‐associated esters, aldehydes, and alcohols, that cannot be detected by other mammals, such as dogs and rats, known for their good sense of smell 55 . Both ring‐tailed lemurs ( Lemur catta ) and humans can track odor plumes 56,57 . Interestingly, capuchin monkeys ( Cebus imitator ) and spider monkeys ( Ateles geoffroyi ) sniff visually “cryptic” (ever‐greenish) or unripe fruits more often than fruits undergoing that change color as they ripen, 58,59 suggesting increased olfactory reliance when visual ripeness cues are less salient.…”

Modality Switching in Landmark-Based Wayfinding

“…Our results imply that humans may very well use their sense of smell to orientate and navigate. According to Cunningham et al (2021), the ability to track olfactory plumes may have been an important skill in foraging. However, this incurred additional cognitive costs, which manifested themselves in the form of a lower relative number of correct decisions and higher mean decision times.…”

“…In the animal kingdom, the ability to orientate by olfactory information has been demonstrated primarily in desert ants (e.g., Steck et al, 2009Steck et al, , 2011Steck, 2012), rats (e.g., Rossier and Schenk, 2003) and dogs (Hepper and Wells, 2005;Reddy et al, 2022). Even untrained ring-tailed lemurs are able to track odor plumes, disproving the traditional belief that primates are unable to do so (Cunningham et al, 2021). Our own research has repeatedly addressed this bias towards vision in human spatial cognition research (e.g., Hamburger and Knauff, 2019) and demonstrated that humans are also able to orient themselves with auditory, visual verbal (i.e., words visually presented on screen) as well as olfactory cues (e.g., Röser et al, 2011;Hamburger and Röser, 2014;Karimpur and Hamburger, 2016;Hamburger and Knauff, 2019).…”