Influence of visual information on sniffing behavior in a routinely trichromatic primate

Most catarrhine primates are considered to be strongly visually oriented animals, obtaining information about conspecifics and their environment from a diversity of visual cues. Other sensory modalities may provide information that is redundant and/or complimentary to visual cues. When cues from multiple sensory modalities are available, these may reinforce or suppress each other, as shown in a range of taxa from insects to humans. In the present study, we tested how the presence and ambiguity of visual information affects the use of olfactory cues when exploring food and non-food items in semi-free ranging Barbary macaques at Affenberg Salem, Germany. In experiment 1, we presented monkeys with pipes containing food (peanuts, popcorn), non-food (stones, feces) or no items. The ends of the pipes were either transparent or opaque, and we assessed whether animals looked, sniffed and/or grabbed into the pipes depending on visibility of the contents. In experiment 2, we manipulated the visua..., We presented monkeys with pipes containing food (peanuts, popcorn), non-food (stones, feces) or no items in transparent or opaque containers and continuously monitored the pipe setups with wildlife cameras. Behaviours of approaching monkeys were scored from the recorded videos. We further manipulated the visual appearance of familiar food items (popcorn) with food colorant and presented dyed and undyed pieces to the monkeys. Behaviours were recorded with a handheld video camera and scored from the videos., , # Influence of visual information on sniffing behavior in a routinely trichromatic primate

[https://doi.org/10.5061/dryad.cnp5hqcdg](https://doi.org/10.5061/dryad.cnp5hqcdg)

We investigated the interplay between visual information and olfaction in two experimental feeding contexts. In experiment 1 (pipe experiment), we provided Barbary macaques with food or non-food items in either a visible or non-visible condition (drainage pipes with transparent or opaque cans) to assess if visibility affected the propensity to sniff at the setup during any stage of exploring it, if visibility affected at what stage of the exploration monkeys used olfaction, and the interplay between visual condition, olfaction and the (attempted) retrieval of items from the setup. Pipe setups were mounted at the bottom of trees at 12 locations within the monkeys' enclosure (in 3 blocks of 4 locations) for 7 full days (with data for some locations expanding until the morning of the 8th day) and were monitored conti...