Elephants

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A really interesting study on knowledge & leadership in elephants, and how age affects their sensitivity to predator threat. The oldest matriarchs are more sensitive to the roars of male lions compared to younger elephants.

Quote:These results demonstrate that while elephant family groups react more strongly to three lions than a single lion roaring irrespective of matriarch age, those led by older matriarchs show a greater sensitivity to the more serious threat posed by male lions across all our behavioural responses, including measures of attentiveness, bunching and mobbing approach. The superior ability to detect the presence of male lions at an early stage— evident in the greater probability of older matriarchs engaging in prolonged periods of listening and defensively bunching with their groups—is likely to have significant survival benefits affording better protection for vulnerable calves in particular. Previous researchers have speculated that elephant groups can derive fitness benefits from the improvement in ecological knowledge conferred by an older matriarch, suggesting that this enables better utilization of scarce resources and predator avoidance during periods of drought [15]. Our work provides the first direct experimental evidence that older matriarchs are in fact able to make better decisions when faced with ecological challenges—in this case, the presence of dangerous predators.

https://www.researchgate.net/profile/Graeme-Shannon/publication/50409036_Leadership_in_elephants_The_adaptive_value_of_age/links/09e41509c1c5822c78000000/Leadership-in-elephants-The-adaptive-value-of-age.pdf

The background:

Quote:Despite theoretical predictions that democratic decision-making should predominate in animal groups [1 – 4], it is becoming clear that specific leaders commonly appear to guide the actions of other group members [5 – 8]. Leaders are therefore increasingly seen as important in coordinating social organization, and there is now grow- ing interest in parallels between leadership in humans and animals that suggest common evolutionary origins, with the same morphological and behavioural traits predicting leadership across species [3]. Understanding the benefits to individual group members of accepting a leader’s decision is critical to uncovering the evolutionary basis of leadership, and hence increasing our knowledge of the role leaders play in human and animal societies [3,9]. One situation in which individuals may gain from following a leader is if older leaders possess some form of superior knowledge enabling better decisions in response to environmental or social triggers [10–12].

Mathematical models of group decision-making have indicated that it may pay individuals in small groups to accept the decision of a knowledgeable leader where large disparities exist in the information possessed by different group members [1]. Indeed, research on humans indicates that age is correlated with leadership in domains that require specialized knowledge [13], and there is recent evidence that decisions about social conflicts improve with age despite declines in many forms of cognitive processing [14]. In animal societies, it has most often been suggested that older leaders provide a vital source of ecological knowledge (e.g. about the location of scarce resources or migration routes), but direct tests of this in natural populations are lacking because of the difficulties in quantifying the relevant skills [6,11,15,16].

A key facet of ecological knowledge that is more amenable to experimental investigation is the ability to respond appropriately to the threat of predators. Moreover, as anti-predator response strategies are often costly and may involve an element of risk [17], the experience to discern when such strategies should be implemented would have critical energetic and survival benefits for individual group members. By using a novel playback paradigm where lion roars were broadcast to simulate varying levels of predatory threat—presented by different numbers and sexes of lions—we were able to investigate directly how groups of African elephants (Loxodonta africana) with leaders of different ages performed at assessing fine-scaled differences in the risk involved. In doing so, we built on techniques previously developed to assess the factors affecting social knowledge in elephant groups [10].

Female African elephants live in matrilineal family units led by the oldest female, or matriarch, who plays a key role in coordinating group movements and responses to threat [10,18 – 20]. Other than humans, lions are the main natural predators of African elephants [21 – 23], typically preying on calves of less than 4 years of age [23,24]. Although it is often assumed that lionesses do most of the hunting, male lions are in fact considerably more effective and successful predators when it comes to targeting the largest prey—namely elephants and buffalo [23,25,26]. These large-bodied species often react to lion attacks with cooperative and aggressive defence mechanisms, presenting formidable opponents given their combined strength and dangerous weaponry [25,27]. In such situations, male lions, being on average 50 per cent larger in body mass and considerably more powerful than females [28], are at a distinct advantage. It is notable that the mean group size for successful male lion hunts on elephants is dramatically smaller than that for successful female hunts (1.8 versus 7 in one key study [23]), a finding also reflected in data on lion hunts of buffalo [25]. Moreover, while hunting success typically increases with group size [22,23], it has been demonstrated that male lions have the capability of overpowering a young elephant even when hunting alone [19,23]. Older elephant matriarchs should be more experienced in facing lion encounters than younger matriarchs, and hence we might expect them to be better able to identify the greater risk posed by larger groups of lions and by male lions in particular. Our study, using individually known elephants in Amboseli National Park, Kenya (see §2), provides an unusual opportunity to examine directly how the age of a leader may influence this vital ecological knowledge in a wild population.

Abilities to discriminate between different levels of predatory threat were tested by giving elephant family units playbacks of three lions versus a single lion roaring and, within these categories, roaring from male versus female lions (see §2). In a wide range of social species, individuals may benefit through increased attentiveness, group-defensive behaviour and, in some cases, even approaches to harass predators (mobbing), which can serve both to directly discourage attack and to gain further information about the threat involved [19,29,30]. While mobbing is not widespread among mammals [17], elephants are sufficiently large and well coordinated to search out and direct group attacks on potential predators [19,27,31]. In conjunction with our previous research on social knowledge in African elephants [10], we predicted that groups led by older matriarchs would show greater attentiveness, defensive bunching behav- iour and increased likelihood of mobbing approach when faced with lion groups (as opposed to singletons) and with males (as opposed to females).

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