Sociality Disrupted: Two Giraffe Studies

One of the ways sociality is coming into clearer view for ethologists is by studying what happens when it is disrupted. The options for doing so are plentiful, given human-induced changes to natural environments and the impacts of conservation practices on the social structures of many species. These options are on display in two giraffe studies—“Proximity to humans affects local social structure in a giraffe metapopulation,” Bond et al, and “Evaluating the social structure of captive Rothschild’s giraffes,” by Lewton and Rose. Building off experimental studies of animals with disrupted social systems, Bond et al analyze how Masai giraffe sociality is impacted by their proximity to traditional settlements (bomas) of indigenous Masai people. In contrast, Lewton and Bond observe aspects of sociality within a “managed social environment”—the Longleat Safari Park, UK. The scope of the respective projects are distinct: Bond et al are drawing on 6 years of field observation of 1,139 adult females in an unfenced, heterogeneous landscape in norther Tanzania; Lewton and Rose report on 12-13 individuals (all born in the Park) over two study periods (2011 and 2015). But both show giraffe sociality as responding to changing circumstances, whether in natural or artificial environment.

Several questions arises about sociality in these two studies. First, is it a robust means by which a species responds to altered environments or is it rather fragile and vulnerable to such disruptions? Bond et al open with a review of far-reaching consequences when social structures are altered, referencing studies of African elephants who’ve been traumatized by poaching, of tree lizards (Urosaurus ornatus) in frequently burned habitats, and in clans of spotted hyenas (Crocuta crocuta) in close contact with humans; but also disruptions induced in experimental studies of zebra finches (Taeniopygia guttata). With the latter group, changes in social structure resulted in lower group foraging efficiency, presumably reducing the fitness of the group. Lewton and Rose, in contrast, argue that “fitness benefits of sociality” can be designed and engineered in managed settings for zoological collections, by understanding “wild social behavior” and trying to replicate some of its environmental dimensions in captivity. Though “disrupted” in a natural sense, it can be reconstituted in an artificial setting. In both cases, social structure is framed as important for advancing conservation concerns broadly. But can it be more directly analyzed, rather than largely regard it as registering effects of the environment? That is, how can we best focus on what’s happening socially with giraffes in these two distinct contexts?

Both studies deploy social network analysis to gauge the relative strength of associations—weaker or stronger ties between individuals. Bond et al both predict and observe a weakening of ties in relation to a population’s proximity to human settlements: “Communities of giraffes that live closer to bomas have weaker relationship strengths among all community members, and have more exclusive social associations with fewer other females.” They speculate that human-generated stressors create “greater difficulty in maintaining group cohesion.” They buttress this speculation with studies that demonstrate that “induced social instability…adversely affected collective action” for social species, as in undermining decision making about movement and other synchronized activities.

Not to doubt that proximity to humans makes life difficult for giraffe populations, but what can be additionally factored in here is culture. Animal cultures are being studied across an array of taxa, all of which turn to some degree on the “within-community” articulation of clustered boundaries among conspecifics. Such cultures are an increasing focus of conservation efforts. Bond et al are close to seeing this as they reference “multilevel social structures,” via which “local preferences in associations among individuals scale up to a number of distinct, but spatially overlapping, social communities.” But with culture, “local” is more than a scaling of up individual preferences; it involves “traditions” passed down through social learning. This is another way to account for communities that “showed extensive spatial overlap and yet were relatively discrete.” Perhaps there are local “dialects” these giraffes learn that inform the boundary work that intensifies when communities face environmental threats. This would suggest that sociality is not weakened as associational ties dissipate; rather, it may be heightened and working more effectively even as groups are reduced in size.

The study by Lewton and Rose, which also features social network analysis, offers a means for thinking about this further. Since they are working in a safari park, they have to align their observations with relationships documented in wild herds. This setting offers something of a scaled down version of the Bond et al study: “Whilst wild individuals can maintain consistent associations with the same herd members, it is common that zoological collections will often control group sizes and composition of captive herds as part of population management goals. Such management practices may restrict opportunities for the formation of consistent social bonds, which are noted as occurring between (particularly female) giraffes in the wild.” Within such constraints, Lewton and Rose ask whether group members are still able to “express social preferences in their choice of associates.” In the right setting (“the correct social environment for calves and mothers”) they find a good deal of socializing, with “significant levels of preferred and avoided associations, with individuals discriminating in their choice of associates.” Part of this involved greater male-female bonds than observed in the wild, due to the spatial constraints of captivity. This is quite intriguing, because it suggests a great deal of both plasticity and strength to giraffe sociality. Also, they observed seasonal variation in social bonding, with animals re-associating after time apart, such that “known companions will still seek out each other’s company when given the opportunity.” In addition to seasonal variations, social choice shifts as animals age, with juveniles being the most gregarious and females becoming more closely associated as they age.

The view from Longleat Safari Park suggests the giraffe social structures in natural settings may mask a good deal of plasticity: “giraffes in captivity appear to alter their time spent socializing based on the social environment they are kept in.” That is, there is a capacity for sociality that emerges and flourishes when presented with different settings. The authors link this “fluidity in social behavior” to physiological changes, but it may also reflect a learned ability or aptitude to respond to shifting relationships within fission-fusion societies. With culture, the focus is on how animals learn to socialize, how they learn proper behavior and to interpret the cues of group members, and—importantly, in a fission-fusion societies—to figure out who belong and who does not, as in giraffe “social cliques,” as documented by VanderWaal et al (2014). Combined, these two studies frame the importance of understanding sociality as more than a response to changing environments.

Recommended Citation

Hartigan, John. “Sociality Disrupted: Two Giraffe Studies.” September 15, 2020. Commentary to Social Theory for Nonhumans. Manifold ed. Minneapolis: University of Minnesota Press, forthcoming. https://doi.org/10.5749/9781452958446.