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.
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).