Family Matters: Elephant Social Structure

By Sophie Wasserman

         A few weeks ago, a friend of mine sent me an article called “This Baby Elephant Being Reunited With Its Dad is the Cutest Thing You’ll See All Day.” And while the video it describes is adorable (what baby elephant isn’t?), and does depict a family reunion, there’s no dad anywhere in the picture. Thus, since Think Elephants is all in favor of education, and this article makes a perfect teaching moment, this week's blog is dedicated to elephant social structure. 

The most basic level of elephant social structure is called the family group. The matriarch (typically the oldest and largest female) is the central figure of the family group, and the rest of members represent generations of her female offspring.  Typically 10-20 individuals make up a family group, and the members spend 70-90% of their time in close proximity to the rest of the group. While females stay with their mother's group for life, a juvenile male elephant will stay with his natal family group until around 10-15 years of age, at which time he will begin to hang out further and further away, until he eventually leaves the family altogether. Once on his own, he may remain solitary, or join up with other males in a loosely bonded bachelor herd. It may seem harsh, but it makes sense evolutionarily; his goal in life is to mate and produce healthy offspring, not an easy task when the only females around you are your mother, grandmother, sisters and aunts.

Family group of African savanna elephants in Amboseli
via Wikimedia Commons

A male will only interact with herds of females when he is looking to procreate, so fathers never have a hand in raising their young offspring. However, female elephants are also never “single mothers.” Females frequently exhibit allomothering behavior, or, in other words, babysitting. Adolescent females, those not quite ready to have their own babies, are often involved in caring for and watching over their younger sisters and cousins.  The mother gains extra comfort, assistance and protection for her calf, and the adolescents learn how to be better mothers to their own future progeny.

Since females stay with their maternal herd, family groups can often grow too large to be supported by the land they inhabit, necessitating a split into two new family groups. These new groups will still spend 35-70% of their time in close association with each other, and thus make up the second tier of elephant social structure, called kinship groups. As populations grow, the final level of organization, “clans,” start to form. Clans on the savannah can consist of anywhere from 50-250 individuals, and are formally defined as kinship groups that share the same geographic range.

Clans can consist of anywhere from 50-250 elephants
via Wikimedia Commons

Important note: All of the above information, as well as much of our assumptions about Asian elephant social structure, is based on research done with African savanna elephants (we’ll talk about forest elephants a bit later). Asian and African elephants inhabit significantly different environments, which has important ramifications not only for differences in how the species lives, but also how we study their behavior. In Africa, most of the work done has been longitudinal observational studies. The open savannas allow for more clear and consistent viewing opportunities, so researchers can park their vehicle a safe distance away and simply observe interactions for hours on end.

Asian elephants, on the other hand, are typically found in more densely packed scrub forests, at time restricting visibility to a few meters away and limiting the opportunities of observational work to the infrequent times when the elephants are encountered in scattered clearings or watering holes.

Asian elephant male on the move, low visibility
via Wikimedia Commons

Some work has been done to try and identify any potential differences in the social organization of Asian elephants. One study in Sri Lanka used behavioral observations, radio collars, and  “molecular scatology,” or the collection of DNA from elephant dung, to establish and study genetic links between closely associated Asian elephants. While the results did suggest that, similar to African elephants, all of the elephants in a family group were of the same matrilineal line (i.e. related through their mothers), the family groups did not seem to organize themselves into larger kinship groups or clans. Additionally, family groups were not as closely associated, only spending on average 30% of their time together.

Once again, one possible explanation for the difference in social structure between Asian and African savanna elephants is differences in their habitats. Mammals in open environments like a savanna tend to cluster in larger groups, while mammals in forested habitats tend to form smaller groups, because of the costs of group living like competition for resources. Support from this claim could be found in further study of the smaller species of African forest elephants, who live in the more densely packed jungle regions of Africa; do they exhibit the same social structure as their savanna relatives, or do they show the less complex organization of Asian elephants since their habitats are very similar? The more we learn about these three species, the more we can understand the environmental factors driving their evolution, as well as the more we can educate the public and protect their currently tenuous existence.

African forest elephant
via Wikimedia Commons

So now that you know about elephant society, can you tell who's really involved in the video below? (Hint: no dads were involved in the making of this adorable clip, but there was still a close-knit family of fearsome females to show this baby some love)

References:

Fernando, P., & Lande, R. (2000). Molecular genetic and behavioral analysis of social organization in the Asian elephant (Elephas maximus). Behavioral Ecology and Sociobiology, 48(1), 84-91.

Thornton, M. (2013, October 14). [Web log message]. Retrieved from http://www.buzzfeed.com/maycie/elephant-family-reunion-hugs-video-addo-park

Media:

Asian elephant panning by Kalyan Varma via Wikimedia Commons

Elephant herd by USAID Africa Bureau via Wikimedia Commons

Herd of elephants by Ben Lieu Song via Wikimedia Commons

Loxodonta cyclotis by Thomas Breuer via Wikimedia Commons

The Elephant in the Classroom

By Elise Gilchrist

            There is a buzzing excitement emanating from the classroom. This will be a very unconventional lesson after all.

            “Settle down! I need to get the connection going first,” exclaims an equally excited teacher.

            “But when will we see them?” “Where are they?” “How close will they be?” A flurry of student enthusiasm is bursting at the seams.

            Then the ringing sound comes clear through the speakers and suddenly the picture expands to reveal...

            “ELEPHANTS!”

            Did you ever think it would be possible to bring a real live elephant into classrooms all over the world? Thanks to the Skype application and web camera technology, that is exactly what Think Elephants International (TEI) has been able to do.

            At TEI we believe that it is important for students to learn about the natural world and the species that live in it. A traditional approach to this lesson plan may include eye-catching photographs or even an enthralling documentary, but how long are those images retained after that lesson ends? It often takes a more memorable, personal experience to get subject matter to really stick in an already saturated mind. That is why we have developed interactive lessons that connect classrooms all over the world with elephants here in Thailand—in real time.

            Our most recent Skype lesson included classrooms in Alaska, Florida, Australia and New Zealand. The students were introduced to two younger elephants, named Thangmo and Am. Our lesson started at 7:00 a.m. Thai time (or 4:00 p.m. in Alaska, 8:00 p.m. in Florida, 11:00 a.m. in Australia and 1:00 p.m. in New Zealand). The students got an opportunity to learn about elephant biology by getting up close and personal with body parts like the trunk, ears, and feet. The students could also ask questions of the TEI elephant researchers. The whole session took only an hour, but we hope that having an elephant live in your classroom is memorable long after the conclusion of the Skype call.

            Utilizing new technologies, innovative teaching methods, and the intrinsic appeal of elephants, Think Elephants hopes to inspire the next generation. If these children can learn to make meaningful, informed choices with regard to the natural world, then we might witness a future where elephants remain alive in the wild.

Pygmy Elephants: The Largest Dwarfs

By Lisa Barrett

Pygmy elephants, dwarf-like versions of elephants, were originally thought to be an entirely different species of elephant altogether. However, research confirms that there are currently only three living species of elephants: Asian elephants (Elephas maximus), Savanna elephants (Loxodonta Africana), and Forest elephants (Loxodonta cyclotis). So, how are pygmy elephants related to elephants who have earned an official species classification?

Borneo pygmy elephants in the Lower Kinabatangan Wildlife Sanctuary.

Photo © Rob Colgan

There has been much debate about the classification of the pygmy elephant. In Africa, the African pygmy elephant used to be classified as its own species, Loxodonta pumilio, but it has since been reclassified as a smaller-sized morph of the African forest elephant. On the other hand, in Asia the Borneo pygmy elephant (Elephas maximus borneensis) is considered to be a subspecies of Asian elephants, and many of them live in the Kinabatangan River Basin (map below) in northeastern Borneo.

Many Borneo pygmy elephants live in the Kinabatangan River Basin.

Photo :www.wwf.org

A study in 2003 by WWF and Columbia University upheld that the Borneo pygmy elephant separated from the Asian elephant about 300,000 years ago, even though people historically believed that the Sultan of Sulu from Java brought the elephants in 1521 to live in Borneo. The Borneo pygmy elephant is about one meter shorter than its mainland counterpart (the Asian elephant) and has a babyish face and straight tusks. Supposedly, pygmy elephants are also less aggressive than mainland Asian elephants.

Differences among African elephants, Asian elephants, and Borneo pygmy elephants.

Photo: News.softpedia.com

What makes pygmy elephants different from dwarfs? Whereas pygmy elephants are a subspecies and smaller version of an Asian elephant, dwarf elephants (who were ancestors of elephant relatives) lived on isolated islands in the Pleistocene era with few predators and resources. Their relatively small environment (compared to that of mainland Asian elephants) with fewer resources selected for their bodies to become reduced in size over many generations. The inverse process of this is called gigantism, when animals—like the dodo—become larger than normal in size in response to having a lack of predators.

Regardless of their classification, the pygmy elephant is in danger of becoming extinct. This is mainly due to habitat loss and human-elephant conflict. In fact, the WWF estimates that there are fewer than 1,500 wild Borneo pygmy elephants. In addition, fourteen pygmy elephants were mysteriously poisoned in January 2013. Pygmy elephants also suffer from habitat loss as land is cleared to make way for palm-oil plantations.

A baby pygmy elephant investigates the body of its poisoned mother.

Photo: http://www.bbc.co.uk/news/world-asia-21241380

References

http://wwf.panda.org/what_we_do/endangered_species/elephants/asian_elephants/borneo_pygmy_elephant/

http://www.bbc.co.uk/news/world-asia-21241380

http://news.nationalgeographic.com/news/2013/01/130131-borneo-pygmy-elephants-killings-animals-conservation-science/ 

A Brief History of the Trunk

Without a doubt, the most versatile and (in our opinion) mind-blowingly awesome appendage in the animal kingdom belongs to our humble elephants: the trunk.  It is used for everything from eating to vocalizing, tool use to heavy lifting.  We know that elephants communicate not only vocally with their trunks, but chemically and tactilely as well.  It is a highly specialized structure that marks the latest strange in the complex evolutionary history of the order Proboscidea.

Anatomically, the trunk is an amazingly complex organ.  It is comprised of over 40,000 individual muscles that run laterally, dorsally, and ventrally.  Within these muscle units are over 150,000 muscle fascicles, or individual fiber bundles.   To give you some perspective, there are approximately 643 muscles in an entire human body.  Elephants also possess a unique facial nerve, called the proboscideal nerve, which runs down the trunk and provides it with hypersensitivity for touch.  With no bones in the entire trunk, elephants possess extreme flexibility and fine dexterity, as well as tremendous strength.  An elephant can lift up to 350 kg with its trunk alone, and can also hold up to two gallons in its trunk at any time.  Thus the muscles of a trunk can not only be used to lift or stretch, but can also expand or contract the nasal passages within to suck in or spray out air and water. 

Photo by Rebecca Shoer

Only three extant (still living) species of the ancient Proboscidea order remain today, these being the two Loxodonta elephant species and our own Elephas maximus.  Although some species, like anteaters, possess similar-looking facial features, they are not members of this elite taxonomic order.  The extended nose of the anteater may look like a trunk, but it is formed by an extension of the entire skull structure: a true trunk is solely comprised of muscles.  The evolutionary history of this ancient order is a complex and puzzling one, and is constantly being questioned and revised by evolutionary biologists. 

As of 2005, scientists believe that, at one time, at least 177 species of Proboscidea existed.  All proboscids share a number of similar traits beyond the trunk, including oversized second incisors (tusks, in some species) and a uniquely rotated wrist bone.  Originating in Africa between 38 and 58 million years ago, the proboscid species adapted in three major events called "radiations."  A radiation occurs when a species moves into a novel environment and undergoes many rapid adaptations, resulting in many species quickly evolving from a single ancestor.  Rather than evolving at a steady linear pace, it seems that proboscids evolved in relatively rapid pulses.  Eventually, proboscids would be found on every continent except Australia and Antarctica.  These earliest proboscids most likely had a mobile upper lip, but did not possess the distinct trunk structure that results from the fusion of the upper lip and nose.  Even today, early fetal elephants have a separated upper lip and nose that eventually fuses in utero.

Elephant fetus from Shoshani, J. Understanding proboscidean evolution: a formidable task.

As time went on, the proboscids developed the familiar trunk structure that we know and love.  But as the trunk is entirely muscle, how can paleontologists know that these ancient animals had them?  There are a number of skeletal features that only proboscids possess, and which strongly suggest that these ancient creatures indeed had trunks.  First, proboscids possess enlarged and elevated bony openings (called "nares") at their nose, which all other mammals lack.  It is possible that a side-effect of these enlarged openings allows elephants to produce the deep infrasonic sounds to communicate across large distances.  Second, proboscids have a large intraorbital canal (an opening in the skull near the eye socket), which allows large blood vessels and nerves access to the trunk.  If skull fossils possess these two traits, scientists can conclude that the ancient animal had a trunk.

Elephant skull, from California Academy of Sciences

The evolution of the trunk may itself have driven the increased brain size of the proboscids and, eventually, of elephants.  Being able to control such a complex organ with exact precision requires massive brainpower, and elephants possess correspondingly large brain regions responsible for motor control.  Perhaps as a consequence of such increased brain mass, other areas of the brain increased as well.  The trunk is just one possible factor driving the development of large brains in today's elephants.

From over 177 species of diverse and highly specialized proboscids, only three species exist today.  Interestingly, despite an overall morphological similarity, Asian and African elephants are not as closely related as one might think.  Indeed, Asian elephants are most likely more closely related to their extinct cousins, the mammoth Mammuthus family, than to  African elephants (of course, this is still hotly contested among Proboscidea evolutionary biologists).  How could a group possessing such a versatile and useful appendage undergo such rapid rates of extinction?  We know that even the earliest humans existed alongside more probodscid species than exist today.  What happened?  There are a number of theories that biologists have posited, and most likely such rapid extinction was due to a combination of these factors.  First, proboscids have relatively long generations, and thus are unable to adapt to changing environments as rapidly as more short-lived species.  Second, the world's climate changed rapidly before and after the last Ice Age, which resulted in a massive extinction in many animal groups.  Third, the heightened specialization of this trunk may have in fact doomed some proboscid species: when an animal becomes too specialized for a single environment, they are unable to adapt to any changes that may occur.  Unfortunately, we are all too aware of the factors driving the current extinction of the remaining proboscids: poaching and habitat loss, all caused by the rapidly expanding Homo sapiens.  The fate of the last members of an entire taxonomic order rests in our hands.