Elephant Sense and Sensibility

by Michael Garstang

  features of the earth, creating a map of the surrounding topography in the mind

  of the bird. Such a map of the bird’s surroundings permits it to find the precise

  location of its dovecot. While it might use other means to determine the gen-

  eral location of its home (the stars, the earth’s magnetic field), these guidance

  systems are insufficiently precise to pinpoint its ultimate destination. With the

  elephant’s highly developed sense of sound, particularly at the very low frequen-

  cies of seismic noise, it is possible that the ability of the elephant to navigate and

  find specific locations is based on the natural seismic sound fields of the earth,

  which humans cannot hear.

  There is further evidence (O’Connell-Rodwell et al., 2000, 2001, 2004, 2012)

  that elephants can project their powerful calls into the near-surface substrate of

  the earth, which then propagate as seismic signals over considerable distances.

  Elephants might be seen as standing on their “fingers and toes” embedded in a

  jelly-like base. Such a base is in excellent contact with the earth’s surface.

  Pacinian corpuscles in the toes and feet pick up transmitted seismic signals

  from other elephants and transfer these signals via the bone structure of the

  detecting animal to its auditory system. In this case, the seismic signal is con-

  verted by the elephant’s brain with sufficient fidelity to allow the receiver to

  identify the sender (O’Connell-Rodwell et al., 2007). We remain unsure as to

  how the elephant recognizes the other individual. Is a visual image constructed?

  Is it simply voice recognition without an image? Is it converted to smell or all

  three? What we do know is that neural processes convert the seismic signal to

  recognition.

  In both of the above cases, neural signals have been interpreted in ways

  unfamiliar to humans. Yet the possibility of sensory signals being converted

  to images by the brain has been demonstrated in humans. Humans can read

  braille through the touch of their fingers. Using a grid of 600 electrodes, Eric

  Weihenmayer is able to “see” using the sensitivity of touch of his tongue

  (Eagleman, 2011). In a condition called synesthesia, people can hear colors,

  taste shapes, and experience other sensory blendings. There is no obvious rea-

  son why animals with brains as complex as those of elephants cannot do the

  same thing. Certainly, there is evidence that cross-talk among sensory areas

  of the brain and visual and auditory systems are closely tied to each other.

  Eagleman (2011) refers to this as the advantage of a “loopy brain”: a brain that

  is able to construct predictions of what will happen based on experience gained

  from the looping of circuits through multiple sensory and neural systems. Here

  perception reflects the active comparison of sensory inputs with internal ex-

  pectations. Eagleman considers the human example of catching a fly ball in

  Functioning of the Brain Chapter | 4 17

  baseball. This involves accurately predicting complex physical processes: the

  striking of the ball and the sound of the bat against the ball, the trajectory of

  the ball involving velocities and accelerations (changes in speed, direction, and

  time), and programming the precise time and location of the simultaneous ar-

  rival of the ball and glove. None of this is done consciously but must be done

  almost instantaneously.1 Yet ultimately it is based on learning and experience.

  So where does the unconscious begin and the conscious end? And if brains are

  able to orchestrate complex operations and rely mainly, if not entirely, upon

  the unconscious, might not animals with adequate brains in which to accumu-

  late and store the unconscious processes be even better than humans in allow-

  ing their unconscious to function without the interference of the conscious?

  Anyone who has mastered a game to a reasonable level of competence has ex-

  perienced the euphoric state of being in the “zone.” You can do nothing wrong

  and play effortlessly at your highest level. Conversely, you cannot consciously

  repeat the performance and the harder you try the worse you perform.

  The role of the conscious and that of the unconscious is exhibited by profes-

  sional athletes all of the time. Those at the top of their respective games, while

  physically capable of performing at the highest level, cannot do so on a consis-

  tent basis. A dramatic example is seen in the struggle that Tiger Woods under-

  went to regain his status in the golf world. There is no doubt that he retained the

  physical skills to do so. What got in his way and prevented him from doing so

  is his conscious mind. In using its large brain might not an elephant be more ef-

  fective in integrating all of the information being received from its sensors, call

  more effectively upon the stored information, recognizing what is important and

  what is not, and do so more effectively than a human? If survival is the measure

  of this process, then perhaps an elephant holds the edge over a human?

  These questions revolve around many issues, not least of which is the im-

  plicit assumption above that elephants (and therefore other nonhuman animals)

  operate far more by the unconscious than the conscious. The immediate flaw

  in the argument is that the unconscious and conscious are not separated but are

  coupled. The degree to which this coupling can function may be as important

  as decoupling one function from the other. In the next chapters, we explore the

  ability of an elephant to modulate its considerable unconscious reserves with

  conscious behavior. Memory, we argue, is fundamental to the effective func-

  tioning of the mind.

  1. The 2013 Nobel Prize in Medicine was awarded to three American neuroscientists, James

  Rothman, Randy Schekman, and Thomas Südhof, for their work in how cells or genes transfer information and substance.

  Chapter 5

  Memory

  We, and elephants, are what we remember (Foer, 2011). Our very existence

  depends on memory. It is possible that everything learned is remembered, yet

  everything remembered cannot be recalled on demand. Even this statement must

  be qualified. In 2006, researchers at the University of California at Irvine re-

  ported on a woman, referred to only as AJ, who was capable of remembering in

  detail, with considerable accuracy, almost everything that happened in her past.

  They proposed the name hyperthymestic syndrome, from the Greek word thymesis, meaning “remembering,” to describe the condition (Parker et al., 2006). Since

  then numerous cases have been recorded of people capable of almost total re-

  call such that the ability to do so is called “superior autobiographical memory”

  (LePort et al., 2012). With this ability to recall manifesting in a small fraction of

  the human population, caution needs to be exercised on the possibility that such

  an ability can exist and be far more prevalent in another species.

  Evolution has dictated that events critical to survival are remembered.

  Humans retain the ability to recall memorable events no longer because re-

  membering them is critical to our survival but because our brains have been

  programmed to remember unusual or critical events. We can vividly recall the

  time, place
, and what we were doing when we heard the news of President John

  F. Kennedy’s assassination or of the attacks on the World Trade Center. Yet we

  cannot remember the name of a person we met just 5 min ago.

  The mind of an elephant, as for all animals, has evolved to recall events

  critical to their survival. An exceptional memory is likely in a highly social

  animal of the size of an elephant. Continual contact and association with other

  elephants plus the neural demands of complex motor functions of a large-bodied

  animal demand a large brain and a good memory (Byrne and Bates, 2009).

  There are three regions that are important to memory consolidation and are

  prominent in the elephant’s brain (McGaugh, 2003). The hippocampus and the

  medial temporal cortex are important to the long-term consolidation of explicit

  memory in the cerebral cortex. Explicit memory, sometimes referred to as episodic

  memory, is memory of specific events. In contrast, semantic memory is derived

  from general knowledge. The caudate regulates body movements and responses to

  learning, which ultimately become automatic, such as knowledge of a frequently

  used game trail leading to a water hole. The amygdala plays a central role in the response to fear and as such may consolidate memories of traumatic events.

  Elephant Sense and Sensibility. http://dx.doi.org/10.1016/B978-0-12-802217-7.00005-3

  Copyright © 2015 Elsevier Inc. All rights reserved.

  19

  20 Elephant Sense and Sensibility

  Memories are formed over time and can be seen to pass through stages. The

  consolidation of memories is not, however, sequentially linked but is based on

  independent processes operating in parallel. Lasting memories consolidate over

  time, even when initially triggered by traumatic events.

  Elephant society is considered to be the most complex among all animals

  except that of humans. Moss (Moss, 1988; Moss and Lee, 2011, pp. 205–223)

  sees the family unit as the core of this social network. Extended families then

  form bond groups, clans, and ultimately entire populations (Figures 5.1–5.3).

  Leggett et al. (2011) and Wittemyer et al. (2005, 2009) have built upon and

  refined Moss’s original social network in an attempt to include fission–fusion

  in the social organization to account for a fluid exchange of members and fam-

  ily units between the basic group and the wider populations. McComb and

  coworkers (McComb et al., 2000) have shown that individual elephants can

  recognize the calls of at least 14 other families, totaling as many as a hundred

  other individuals. Such a feat of individual identification would test the mental

  abilities of humans. Elephants keep track of family and bond group members

  on a continual basis. Low-frequency contact calls (rumbles) are emitted on a

  frequent if not near-continuous basis. These calls serve to maintain cohesion of

  the family group, defining the territory occupied and alerting other groups to

  their presence.

  FIGURE 5.1 Very powerful bonds are established during the long period of nearly 2 years of close contact between mother and calf. Females will remain within their family unit throughout their lifetime. Males will leave or be made to leave their family at puberty. They may well return briefly during their lifetime.

  Memory Chapter | 5 21

  FIGURE 5.2 All members of the bond group will have close family ties. One elephant will recognize by sound, smell, touch, taste, and sight more than 100 other elephants within their home population.

  FIGURE 5.3 Fluid movement, known as fission–fusion, between bond groups and populations exhibit a social network unique amongst terrestrial animals with the possible (past) exception of humans. The role and importance of this extensive bonding is unknown but potentially vital to the survival of this species.

  22 Elephant Sense and Sensibility

  While their vision in bright light is not good, perhaps limited beyond 50 m

  (160 ft), elephants detect and are very sensitive to subtle body language involv-

  ing ears (flapping, raising, folding), trunk, tusks, feet, tail, and whole body.

  Olfaction and chemical communication combined with the use of touch add

  to the complexity of memory functioning in a highly social system.

  Experienced elephant matriarchs, carrying perhaps generations of knowledge

  passed on by successive predecessors, demonstrate higher rates of survivability

  in times of famine and drought (Foley et al., 2008) and higher reproductive rates

  within their herd (McComb et al., 2001) (Figure 5.4). The ability to transfer this knowledge to successive generations of elephants is a direct function of their

  longevity and strong social bonds. Female elephant offspring remain in the fam-

  ily unit throughout their lives. Future matriarchs of a herd are frequently the

  daughters of the herd matriarch (Figure 5.5). Knowledge embedded within the memory of the matriarch is transferred through experience over as much as 40

  or 50 years. Long-term memory not only allows these elephants to recall remote

  locations but allows them to find these locations across considerable distances of

  featureless country (recall the introductory description of finding isolated oases

  in the Namib desert after not visiting these locations for more than 20 years).

  Memory also serves to determine where and when specific food may be

  found and when it is edible. Cochrane (2003) has postulated that elephants

  adopt specific pathways that are committed to memory and lead to fruit-bearing

  trees, Balamites wilsonia, which are rich in proteins, fats, and diosgenin.

  FIGURE 5.4 The matriarch leads the herd, drawing on a vast store of spatial memory that serves to preserve the herd.

  Memory Chapter | 5 23

  FIGURE 5.5 A calf learns to identify mother and members of its family by sound, much of which may be below human hearing, touch, taste, and smell, with vision probably being last of the senses to be relied upon. All of this information is to be stored in short- and long-term memory.

  The Mfuwe Lodge in the South Luangwa National Park in Zambia inad-

  vertently enclosed wild mango trees in the interior atrium of the lodge. These

  mangoes ripen in November of each year, lasting for 4–6 weeks. A family

  unit of 10 elephants, led by their matriarch, Wonky Tusk, have returned to

  these mango trees from somewhere in the 9500 km2 (3700 mile2) national park

  in each November of the past 4 years. Wonky Tusk has led her group into

  the lodge, past the reception desk, to feed upon these mangoes without show-

  ing any aggression or fear of humans in the lodge (Carter, 2008; http://www.

  africatravelguide.com/articles/the-elephants-of-mfuwe-lodge.html).

  Elephants can recognize other elephants as well as humans after being sepa-

  rated from each other for many years. Buckley (2009) at the Elephant Sanctuary

  in Hohenwald, Tennessee, reports that in 1999, Jenny, a resident elephant, was

  introduced to a newcomer, Shirley, an Asian elephant. Both elephants became

  animated, vocalizing loudly and using their trunks to check each other out.

  Neither exhibited any aggression, both displaying what observers described as

  a “euphoric emotional reunion.” Probing the history of the two elephants, it

  turned out that Shirley and Jenny had been together in the Carson and Barnes

  Circus for a few months, 23 years earlier.

  Elephants have highly sensitive olfactory and chemical detection capabil- />
  ities. Within the nasal cavity of an elephant are seven turbinates (dogs have

  five), which are scrolls of bones with sensitive tissues to detect smell and which

  contain millions of receptor cells. In addition, elephants have a Jacobson’s or

  24 Elephant Sense and Sensibility

  vomeronasal organ on the roof of the mouth. This organ is highly sensitive to

  flemen, which is sampled by contact with the tip of the trunk and is then brought

  to the roof of the mouth. Sources of these odors are urine, feces, saliva, and the

  excretion of the temporal gland as well as the genitals found in both male and

  female African elephants. Adult African elephants of both sexes have a gland

  located at the temple which results in a dark stain marking the sides of their

  heads when agitated or stressed. Indian male elephants, but not females, show

  a similar glandular response, especially when in the heightened sexual state of

  musth. Elephants are seen to be touching and sampling these sources using the

  tip of their trunk.

  Bates et al. (2008a) tested elephants’ ability to keep track of their social

  companions using olfactory cues in urine. They found that in this way elephants

  can recognize up to 17 females and possibly 30 family members. Keeping track

  of this number of individuals is cognitively challenging and places considerable

  demands on the animal’s memory capacity.

  When the stable isotopes of oxygen, hydrogen, and nitrogen embed-

  ded in elephant tusks were related to the water holes of Etosha National Park

  (Dieudonne, 1998), the territories of the best matriarchs were found to be coin-

  cident with the best water sources.

  It is likely that elephants have developed multiple sensory inputs of the kinds

  discussed earlier, including in particular a range of audible and inaudible (to

  humans) biotic and abiotic signals together with olfactory and chemical signals

  to produce exceptional spatial mapping skills. These mapping skills rely upon

  and interact with long-term memory skills vested in and passed on in successive

  generations by the matriarchs of the herd. Such abilities have direct survival

  consequences so that matriarchs occupy the best territories with respect to food