Elephant Sense and Sensibility

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by Michael Garstang


  isolated oases to drink and feed on preferred vegetation.

  The Angolan civil war (1975–2002) decimated and dislocated wildlife in

  this region. It is estimated that 100,000 elephants were exterminated in Angola

  alone. Wildlife in Namibia was also disrupted by military operations and by

  poaching. A north–south road, built for military purposes in Namibia, cut off

  migrations from the east (Etosha National Park) to the coastal deserts of north-

  western Namibia.

  With independence in Namibia and a fragile peace in Angola (Figure 1.2),

  the blocking road was closed. Elephants could once again penetrate the des-

  ert. Reaching the nearest oasis meant a 24-h walk, across shifting desert sands,

  climbing up and over 100-m (300-ft) dunes in a featureless terrain devoid of

  landmarks. Elephants who had not made this journey for more than two genera-

  tions unerringly crossed these sands to revisit favored isolated sites. Whether or

  not the elephants that made this amazing journey had done so before still leaves

  the questions: How did they navigate across such hostile and featureless terrain

  to find a precise and isolated location? And, how and why did they remember

  these remote clusters of green in a vast sea of undulating sand?

  Similar journeys have been recorded covering some 180 km (112 mile) from

  the Caprivi Strip and Botswana by elephants returning to Angola’s Luiana Partial

  Reserve (Leon Marshall, January 2008, Sunday Independent [South Africa]).

  This reserve in Cuando Cubango Province was occupied by Jonas Savimbi’s

  N ational U nion for the T otal I ndependence of A ngola (UNITA). Savimbi’s rebels distributed unknown numbers of landmines in the region. Michael Chase

  of Elephants Without Borders (Chase, 2007; Chase and Griffin, 2011) knows

  of the location of some 45 minefields near Jamba Camp, Savimbi’s old head-

  quarters. After the end of the civil war in 2002 when elephants began returning

  to the Luiana Partial Reserve, many were fatally injured by these land mines.

  Chase, however, reports that within 2 years no incidents of injury or loss of

  elephants in the region were reported. By using overlapping tracking of five

  Elephant Sense and Sensibility. http://dx.doi.org/10.1016/B978-0-12-802217-7.00001-6

  Copyright © 2015 Elsevier Inc. All rights reserved.

  1

  2 Elephant Sense and Sensibility

  FIGURE 1.1 Desert elephant, Loxodonta africana, adapted to the sands of the Namib and Kalahari. Taller and more slender than its fellow elephants on the wetter savannas, the tallest on record is 4.5 m (14 ft, 4 in.) at the shoulder.

  FIGURE 1.2 Points of interest in Southern Africa that appear throughout the text: (1) Namib Desert and Skeleton Coast; (2) Etosha National Park; (3) Okavango Delta; (4) Luiana Partial Reserve; (5) Caprivi Strip; (6) Luangwa National Park; (7) Sengwa National Park (formerly Wanki); (8) Kruger National Park; (9) Pilanesberg National Park; (10) Hluhlwe Game Reserve; (11) Addo Elephant National Park; (12) Knysna Forest; (13) Kalahari; and (14) Parque National do Limpopo.

  Introduction Chapter | 1 3

  GPS-collared elephants, Chase demonstrated that these elephants (both collared

  and herd mates) were moving through minefields without injury. It would be

  difficult not to conclude that the elephants had learned to detect the presence of

  mines, knew that the mines represented danger, and were able to avoid them. It

  is equally likely that these elephants used their highly refined sense of smell to

  detect the mines.

  Responding to the changing circumstances described above, elephants dem-

  onstrate cognitive abilities and adaptability that are remarkable. The ability to

  find remote locations in trackless landscapes, to deal with threats to their sur-

  vival, and to formulate solutions that can be followed by the group as a whole

  draw upon advanced mental processes. Elephants depend on memory, making

  the origins of memory fundamental to elephant neural processes. Memory is

  thus a central theme of this book. We as humans are what memory makes us.

  Without memory we cease to exist as sentient beings. This is no less true for

  elephants than it is for humans.

  In Chapter 2 we trace the evolution of elephants with particular attention

  to aspects of the elephant’s brain that reflect this evolution. Elephants deviated

  from the primates some 35 million years ago. Yet elephants, proceeding in par-

  allel, evolved brains that are functionally more similar to those of humans than

  they are different. With large bodies and complex systems such as the trunk and

  an opposable thumb in the form of a highly tactile and sensitive tip (Figure 1.3),

  elephants exhibit cognitive abilities that may in some instances exceed those of

  humans. Because human brains have been studied much more extensively than

  those of elephants, in Chapter 4 we make some comparisons between these two

  brains.

  In Chapter 3 we examine physiological aspects of the elephant’s brain

  but in concert with current neurological research (Bryne and Bates, 2006);

  we are more concerned with how the brain as a whole functions rather than

  the role played by the component parts of the brain. In particular, we attempt

  the difficult task of entering the mind of the elephant, despite the constraint

  of the imbalance of our knowledge of the elephant versus the human brain

  (Gould, 2004).

  We take a Darwinian approach, arguing that evolution favors behavior that

  promotes survival of the species (Darwin, 1897). This will lead us to explore

  in elephants the existence and the origin of memory (Chapter 5), morality

  (Chapter 6), emotions (Chapter 7), empathy and altruism (Chapter 8), commu-

  nication (Chapter 9), language (Chapter 10), intelligence (Chapter 11), learning

  and teaching (Chapter 12), the sensory environment (Chapter 13), and the rela-

  tionship between humans and elephants (Chapter 14). Each of these character-

  istics is embedded in the cognitive processes of the elephant’s brain and is thus

  uniquely elephantine.

  We draw upon the growing body of scientific evidence that examines these

  areas and while we are able to consider significant findings, these will not be

  without contention, nor in many cases fully supported by definitive scientific

  4 Elephant Sense and Sensibility

  FIGURE 1.3 The versatility of the trunk is enhanced by the two fingers or the equivalent of an opposable thumb at the tip of the African elephant’s trunk. The sensitivity and control of this prehensile feature allows the detection of minute surface features or the picking-up of objects as small as an unshelled peanut.

  evidence. Few animals can be subjected to rigorous and controlled experiments.

  This is not only for ethical reasons but as we show, failure to replicate natural

  conditions can invalidate or bias many experiments that are carried out under

  artificial conditions. Conversely, however, it is difficult to conduct rigorous ex-

  periments under presumed “natural” conditions. In many instances, we draw

  upon unverified anecdotal evidence not as proof of a concept but as possible

  guidance to the development of a testable hypothesis or the formulation of a

  question (Byrne, 1997; Byrne and Bates, 2011a; Heyes, 1993).

  In conclusion, we ask whether our findings cast light upon the relationship

  between ourselves and our fel
low beings who occupy this planet with us, ad-

  dressing the troubling question of what endows humans with significant privi-

  leges over animals.

  Chapter 2

  Elephant Evolution

  Darwinian evolution, alluded to in the previous chapter, is seen in contemporary

  biology in complex and sometimes conflicting terms. We subscribe by and large

  to the views on evolution as developed by Richard Dawkins in both The Selfish

  Gene (1989) and The Extended Phenotype (1999). Our approach, although predicated upon the following discussion of how Dawkins might view evolution, will

  in many cases point only to a simplified conception of how crucial characteristics

  of elephant behavior might have evolved, without entering into the complexities

  of how or perhaps even whether, in fact, this may have taken place.

  Dawkins (1989) holds that “the fundamental unit of selection, and therefore

  of self interest, is not the species, nor the group, nor even, strictly, the individ-

  ual. It is the gene, the unit of heredity” (p. 11). Dawkins sees natural selection

  leading to stable forms of life with high longevity, fecundity, and copying fidel-

  ity coded within the DNA of the individual (see pp. 18–23, 41). Given that life

  begins with the gene, aggregating into what are referred to as phenotypes and

  residing in a transfer mechanism he describes as a replicator, Dawkins (2008)

  does not neglect nor deny the existence of complex individual organisms. He

  sees the organism as a physically discrete machine, with essential internal orga-

  nization. It is a definable unit, with a unique collection of the same genes. Yet, it

  is different from all other organisms. It has its own coordinated central nervous

  system such that “all its limbs conspire harmoniously together to achieve one

  end at a time” resulting in “intricate orchestration, with high spatial and tem-

  poral precision, of the hundreds of muscles in the individual” (pp. 250–251).

  Copying errors will occur, resources will be stressed, and competition can

  delete the less favored, but nothing controls the process. “Trivial tiny influences

  on survival probability can have a major impact on evolution. This is because

  of the enormous time available for such influences to make themselves felt”

  (Dawkins, 1989, p. 4).

  Evolution does not act for the good of the species but for the survival of

  the individual (perhaps “selfish”) gene. Yet these self-preserving, genetically

  inherited traits under certain circumstances might serve to promote that society.

  For this to happen, Dawkins claims “that we shall be faced with something

  puzzling, something that needs explaining” (p. 4). The male may be banished

  from the group and be forced to compete and distribute his selfish genes among

  many different groups. These groups, guided by a single female who occupies

  Elephant Sense and Sensibility. http://dx.doi.org/10.1016/B978-0-12-802217-7.00002-8

  Copyright © 2015 Elsevier Inc. All rights reserved.

  5

  6 Elephant Sense and Sensibility

  her position not through conflict but by an approximation to acclimation, not

  only nurtures her young for a long period of time but retains a high proportion

  of her female offspring within a single group for their entire extended lifetime.

  Perhaps this is the unusual circumstance that is needed for the selfish gene to

  contribute or be displaced in order that the species survives?

  A significant part of the content of the pages that follow documents how

  elephants might be the unique species of animal that most closely meets the

  unusual circumstances demanded by an evolutionary mechanism centered upon

  the propagation of genes.

  Proboscideans, the ancestors of today’s elephants, can be traced back in time

  for more than 35 million years (Figure 2.1). They evolved in dense, closed-canopy forests. By the time that Elephantidae in the form of the mammoth and

  present-day Asian ( Elephas maximus), African savanna ( Loxodonta africana), and forest ( Loxodonta cyclotis) elephants emerged as distinct species, the forests had receded, giving way to savannas. Because of this evolution within a

  forest, elephants emerged onto the open savannas with capabilities formed

  in the forests. Their sense of hearing and smell had evolved in favor of sight.

  Elephants were thus capable of both emitting and detecting calls over the widest

  range of frequencies of any animal. Their eyesight was poor, adjusted more to

  the restrictions of dense vegetation than to the vistas of the savannas.

  Dawkins (1989, p. 7) relates a story told by Colin Turnbull who took a

  pygmy friend, Kenge, out of the forest for the first time in his life. They climbed

  a mountain and had an extended view over the plains where in the far distance

  a herd of buffalo were grazing. Kenge turned to Turnbull and asked, “What

  insects are those?” Puzzled by the question, it took Turnbull a moment to realize

  that in the limited vision of the forest there was no need to adjust for distance

  when judging size. Without any experience of using known objects as a basis for

  comparison, Kenge was unable to interpret the size of what he saw.

  The vertical structure of temperature, moisture, and wind in the forest

  favored long-range transmission of low-frequency sounds with wavelengths on

  the order of meters to tens of meters rather than centimeters. Trees and vegeta-

  tion have little attenuating affect on sounds with such long wavelengths. Wind

  speed and turbulence, which effectively destroy sound and limit the distance

  over which sound travels, are low to nonexistent in the forest. Temperatures at

  the cool floor of the forest are, especially during the day, much lower than at the

  sunlit forest canopy, resulting in an increase in temperature from the floor to the

  tops of the trees. This phenomenon, called a temperature inversion, results in

  denser air (lower temperatures) at the surface and less dense air (higher tem-

  peratures) at the tops of the trees. Sound waves produced at the surface in such

  a layer of air are bent first upward and then downward as their speed changes

  with lower and higher temperatures. The sound wave effectively bounces down

  this inversion channel. This ducting of sound allows the calls of elephants to be

  heard by other elephants at distances of kilometers. A similar temperature gra-

  dient is present in the world’s oceans, where it is known as the SOFAR channel

  Elephant Evolution Chapter | 2 7

  FIGURE 2.1 Simplified diagram of the emergence of true elephants (family Elephantoidea) (after Shoshani, 2002). Red lines show the geologic periods and associated times. The heavy continuous black line shows the evolution of Elephas maximus and Loxodonta africana ( Loxodonta cyclotes not shown). The subsidiary lighter/dashed lines show some but not all of the extinction of families. Credit and permission derived from Vladimir Nikolov and Dr. Docho Dochev, Department of Geology, Paleontology and Fossil Fuels, Sofia University, Sofia, Bulgaria.

  8 Elephant Sense and Sensibility

  or thermocline and is used by marine mammals such as whales to send signals

  to conspecifics thousands of kilometers away. The utility of this ability to com-

  municate over vast distances can be measured not only in terms of finding mates

  but of being able to use food resources separated by many hundreds of miles


  of barren ocean. The ability not only to know where food is but to have unob-

  structed access to these locations is something that terrestrial animals are being

  progressively denied as their habitats shrink and migration routes are severed.

  In a rather surprising twist of fate, the dry savannas that most of the elephants

  now found themselves occupying exhibit a powerful night-to-day reversal in

  acoustic conditions. Cloud-free, dry atmospheres of the savannas allow the day-

  time heat gained through absorption of solar radiation to stream upward and

  outward to space as soon as the solar angle drops toward sunset. The loss of

  outgoing longwave or terrestrial radiation operates to rapidly cool the earth’s

  surface. Surface temperatures that may have approached 45–50 °C (113–122 °F)

  in the middle of the day and early afternoon now drop precipitously to 10 °C

  (50 °F) or lower, producing a daily range in temperature of some 40 °C (72 °F),

  more than many locations on earth experience from the hottest summer day

  to the coldest winter night. A very strong and shallow nocturnal inversion is

  formed, allowing loud elephant calls to be heard by another elephant as much

  as 10 km (6 mile) away. This ability to communicate over such great distances

  translates to being heard over an area of greater than 300 km2 (112 mile2). Such a

  reach in communication is crucial to elephant reproduction, predator avoidance,

  and resource utilization, all factors that we examine in terms of their behavior,

  social structure, and cognition (Garstang et al., 1995, 2005; Larom et al., 1997).

  Conversely, during the day when surface temperatures rise above 40 °C,

  plumes of rising air generate turbulence and turbulent mixing. Because winds

  above the surface are always stronger than at the surface, these turbulent eddies

  bring higher winds to the surface, exacerbating the turbulence and attenuation of

  sound. Under the worst daytime conditions, elephant calls that traveled 10 km

  (6 mile) and covered 300 km2 (112 mile2) during the early evening can now only

  be heard 1 km (0.6 mile) away and only over an area as small as 3 km2 (1.3 mile2).

 

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