Spatial mapping shows that some African elephants use cognitive maps to navigate the core but not the periphery of their home ranges

Abstract

Strategies of navigation have been shown to play a critical role when animals revisit resource sites across large home ranges. The habitual route system appears to be a sufficient strategy for animals to navigate while avoiding the cognitive cost of traveling using the Euclidean map. We hypothesize that wild elephants travel more frequently using habitual routes to revisit resource sites as opposed to using the Euclidean map. To identify the elephants' habitual routes, we created a python script, which accounted for frequently used route segments that constituted the habitual routes. Results showed elephant navigation flexibility traveling at Kruger National Park landscape. Elephants shift strategies of navigation depending on the familiarity of their surroundings. In the core area of their home range, elephants traveled using the Euclidean map, but intraindividual differences showed that elephants then converted to habitual routes when navigating within the less familiar periphery of their home range. These findings are analogous to recent experimental results found in smaller mammals that showed that rats encode locations according to their familiarity with their surroundings. Additionally, as recently observed in monkeys, intersections of habitual routes are important locations used by elephants when making navigation decisions. We found a strong association between intersections and new segment usage by elephants when they revisit resource sites, suggesting that intersection choice may contribute to the spatial representations elephants use when repeatedly revisiting resource sites.

Arboreal route navigation in a Neotropical mammal: energetic implications associated with tree monitoring and landscape attributes

“…In order to construct a habitual route network, we first overlaid all daily travel paths recorded during the same week per group onto a raster map of the area and checked their concordance [18]. Whenever a daily path fell within a 10 m buffer of another daily path of that week for at least 15 m without deviating more than 45° from the other path, we considered it as the same travel segment [11]. We selected these parameters in order to be consistent with previous research [18, 51–53] and to control for GPS accuracy and travel directionality [52, 53].…”

“…Although the elements that construct such spatial representation are still debated [8], the ability to navigate flexibly in space has been suggested to be indicative of sophisticated cognitive maps and, hence, enhanced cognitive abilities [9]. For instance, some animal species have been suggested to compute distances and angles based on features of the landscape as in an Euclidean representation of the area (e.g., honey-bees, Apis melifera , [10], African elephants, Laxodonta africana , [11], chimpanzees, Pan troglodytes , [9]). Contrarily, the most common navigation strategy associated with cognitive maps is the repeated use of paths, here referred to as “habitual routes” (insects [12], birds, [13], mammals, [14, 15], humans, [16]).…”

Importance of old bulls: leaders and followers in collective movements of all-male groups in African savannah elephants (Loxodonta africana)

“…Elephants possess detailed spatial knowledge of their core range, within which they travel using a “Euclidean-cognitive map” 15 . However, when navigating the periphery of their range, elephants switch to using habitual routes 15 .…”

“…Elephants possess detailed spatial knowledge of their core range, within which they travel using a “Euclidean-cognitive map” 15 . However, when navigating the periphery of their range, elephants switch to using habitual routes 15 . After prolonged use, these habitual routes can lead to “elephant pathways”, which are proposed to facilitate optimal foraging strategies by connecting predictable resources and landscape features such as drinking points 16 .…”

Travel linearity and speed of human foragers and chimpanzees during their daily search for food in tropical rainforests

“…The ecological intelligence hypothesis has proposed that spatial cognitive abilities have evolved in complex foraging contexts to locate scattered and ephemeral food sources within seasonally fluctuating environments 1–5 . A wide range of animal species from insects to primates use spatial memory for foraging (e.g., bees 6 , birds 7 , elephants 8 , mangabeys 9 , baboons 10,11 , chimpanzees 12,13 ), and the variation in their abilities to solve spatial tasks provides a unique opportunity for testing this hypothesis. Large-bodied animals with generally large home ranges likely have a greater need to remember food locations within their natural habitats and to navigate efficiently between them to reduce travel costs 14 .…”