Effects of proximity and activity on visual and auditory monitoring in wild Japanese Macaques

Abstract

Group-living primates monitor group members to maintain the spatial cohesiveness of the group. We examined the possibility that visual scanning (turning the head for more than 3 sec) and contact calls (coo calls) function as visual and auditory monitoring behaviors to avoid separation from group members in wild Japanese macaques. The rate of visual scanning increased as proximity to group members decreased and as mobile activities (foraging and moving) increased, compared with immobile activities (resting and grooming). However, the rate of contact calls varied differently with proximity and activities. During resting and moving, the rate of contact calls increased as proximity decreased. In contrast, the rate increased with closer proximity during feeding. Visual scanning during all activities and contact calls during resting and moving increased when the group members were likely to spread over a larger area, suggesting that these behaviors functioned as monitoring of group members to avoid separation from the group. Contact calls also increased when the group members stayed in close proximity during foraging, suggesting that this behavior was also associated with competitive situations. Contact calls may also function to ease tension or maintain distance to avoid conflict in competitive situations.

What have we been looking at? A call for consistency in studies of primate vigilance

“…Robinson (1981) found that wedge-capped capuchins (Cebus olivaceus) increased vigilance with increasing distance to nearest neighbor; conversely, Suzuki and Sugiura (2011) reported vigilance increased as distance to nearest group member decreased in Japanese macaque (Macaca fuscata) adult females. Baldellou & Henzi (1992), Busia et al (2016), de Ruiter (1986, Fragaszy (1990), Gould et al (1997), Isbell & Young (1993), Rose & Fedigan (1995), Steenbeek et al (1999), Stojan-Dolar & Heymann (2010) a , Treves (1998Treves ( , 1999c, van Schaik & van Noordwijk (1989), Watson et al (2015) No difference between sexes Cowlishaw (1998), Gould (1996), Gould et al (1997), Macintosh & Sicotte (2009), Smith, Kelez & Buchanan-Smith (2004, Teichroeb & Sicotte (2012), Treves (1998) Dominance Subordinates more vigilant than dominants Alberts (1994) b , Caine & Marra (1988), Gaynor & Cords (2012), Haude et al (1976), Keverne et al (1978), Pannozzo et al (2007) High-ranking individuals more vigilant Alberts (1994) c , Gould (1996), Gould et al (1997), Isbell & Young (1993), Rose & Fedigan (1995), Watson et al (2015) No effect of rank Robinson (1981) Adult females with Infants…”

“…Terms such as "gaze", Numerous studies appear to try and tackle this problem by using postural changes or eye movement in elements of their vigilance definitions ( Table 2). Some of these definitions take a very concise multifunctional form such as "head up, eyes open" (Cowlishaw, 1998) or "movement of the head and/or eyes" (Gaynor & Cords, 2012), whilst other authors have added postural requirements to vigilance definitions such as "lifting of the head" (Caine & Marra, 1988) or "turning the head" (Suzuki & Sugiura, 2011). Some are more precise such as "Raising and lowering of the line of vision by at least 30 degrees relative to the horizontal plane" (Bshary & Noe, 1997), or "Head movement of at least 458, in any direction" (Steenbeek et al, 1999).…”

“…Where applied, however, the number of intervals containing vigilance can be used directly in subsequent analysis (Bshary & Noe, 1997) but more commonly the frequency of vigilant intervals is expressed as a proportion of total interval frequency, yielding percentage of vigilance. Percentages can be expressed per individual (Tsingalia & Rowell, 1984), experimental condition (Koenig, 1998), age-sex class (Fragaszy, 1990;Gosselin-Ildari & Koenig, 2012), or for each socioecological condition under investigation (Gosselin-Ildari & Koenig, 2012;Steenbeek et al, 1999;Suzuki & Sugiura, 2011).…”

“…A key factor in one-zero sampling is the choice of interval length, which has proved variable in primate vigilance literature, varying from 5 s (Gosselin-Ildari & Koenig, 2012;Koenig, 1998) though 10 s (Bshary & Noe, 1997), 30 s (Tsingalia & Rowell, 1984) and 60 s (Steenbeek et al, 1999;Suzuki & Sugiura, 2011) intervals. In addition, Fragaszy & Chapman (1996), Cords (1990Cords ( , 1995, Smith, Kelez & Buchanan-Smith (2004) a , Treves (1998Treves ( , 1999a 90 s 1 Gaynor & Cords (2012) 2 min 4 Treves et al (2001), Treves et al (2003), Treves & Brandon (2005), Kutsukake (2007) 3 min 1 Caine & Marra (1988) b 5 min 2 Caine (1984), Keverne et al (1978) b 8 min 1 Kazahari & Agetsuma (2010) 10 min 6 Alberts (1994), Gould et al (1997), Hall & Fedigan (1997), Macintosh & Sicotte (2009), Rose & Fedigan (1995, Teichroeb & Sicotte (2012) 15 min 5 Busia et al (2016), Dunbar (1983), Gould (1996), Gould et al (1997) questions, many preclude the ability to look at vigilance scheduling and the temporal organization of vigilance (Beauchamp, 2015 …”

“…Looks towards observers have been recorded and excluded (Koenig, 1998;Pannozzo et al, 2007), simply not recorded (Suzuki & Sugiura, 2011), or grouped with other forms of reactionary vigilance and classified as "anti-predator" vigilance (Hirsch, 2002). MacIntosh & Sicotte (2009) recorded and retained vigilance data in which study animals directed vigilance towards observers and other humans, leading to human related factors being considered as possible driver of vigilance use in ursine colobus.…”