Inside the Forest Elephant Social Network

by | 28th July 2014



By David Brown

Lopé National Park. Photo by Stephanie Schuttler.

Stephanie Schuttler awoke to something clattering around outside her bedroom, knocking over garbage cans and ripping leaves off of trees.

If she were back home in North America, then she might think that it was a raccoon or an opossum.

The animals outside her room then started knocking down window panels and ripping the plumbing out of the bathroom a few rooms down from Stephanie.  They were trumpeting and making agitated rumbles.

Those were not raccoons.

They were forest elephants outside of a cabin at the Station D’Etudes des Gorilles et Chimpanzes, a research station in Lopé National Park in the Central African country of Gabon.

Stephanie recounts her experience with the elephants that night: “Outside of my room an elephant tried to climb the stairs leading up the front porch. It pushed my door in with its trunk, but the door held, luckily, being locked from the inside.  I decided it was no longer safe to stay in bed. I leapt out of bed to the opposite side of the room. There was no time to grab a flashlight and the moon was dull, so I only saw darkness. I heard wood breaking and falling, but the noise was coming from inside my room. There were two other researchers in the rooms next to mine and I called out “They’re coming in my room!”

She quietly went into her colleague’s room next door.  They huddled quietly and the elephants eventually went away.

Forest vs. Savannah Elephants

Forest elephants are smaller than savannah elephants. Photo by Stephanie Schuttler.

Stephanie was in Gabon to study the social networks of the forest elephants. The elephants dismantling Stephanie’s cabin were not there to “friend” her and join her social network, however.

Social networks are the connections of social interactions and personal relationships that individuals have with each other.  Humans maintain social networks with their families and friends, the people that they go to school and work with, and electronically with other people around the world.  Elephants similarly have social networks with other elephants.

There are two species of elephants in Africa.  The savanna elephant lives in the savanna grasslands of East and Southern Africa.  The savannas are very dry and open grasslands.

The other kind of elephant, the forest elephant, lives in the African rainforests of West and Central Africa.  The tropical rainforests are very wet and enclosed with trees, vines, and other plants.

African savanna elephants are the largest living land mammals on Earth.  Forest elephants are smaller than savanna elephants.  Both kinds of elephants have large ears.  Savanna elephants have ears shaped that are somewhat pointed on the bottom.  The ears of forest elephants are typically more round on the bottom.  Both savanna and forest elephants have tusks.  Savanna elephants have tusks that are usually more curved.  Forest elephant tusks tend to be straighter than savanna elephant tusks. Forest elephant tusks can have a yellow or may have a pinkish color.  Some scientists think that the forest elephant tusks may have evolved this way to create less resistance for traveling through the forest.

Forest elephants also have straighter tusks than savannah elephants. Photo by Stephanie Schuttler.

A savanna elephant meets and associates with many individuals in its lifetime.  Savanna elephants live in matrilineal herds with an older female, a matriarch, as a leader.  Several females and their calves live together in family groups.  This herd structure helps protect the elephants against predators and helps them find food and water.  Different family groups of savanna elephants will hang out with each other at various times of the year.  During the wet season in countries like Kenya many family groups may come together and form groups of hundreds of elephants.  Savanna elephants have very large and active social networks.

Forest elephants are seen in much smaller groups than the ones formed by their cousins on the savannas.  The forest elephant species lives deep in the rainforests of Central and West Africa where they cannot be observed as well by scientists as savanna elephants can be.  This means that much of what goes on in the lives of forest elephants is a mystery and raises many questions:  How big is a forest elephant social network compared to a savanna elephant social network?   How many individuals is a forest elephant hanging out with and what are they doing when they get together?  Do forest elephants get together as much as savanna elephants do?  Stephanie Schuttler set out to investigate these questions by observing their behavior and analyzing the genetic relatedness of individuals to each other.

Elephant-Watching!

Stephanie observes a group of forest elephants. Photo by Stephanie Schuttler.

Stephanie and her field team first had to identify the forest elephants in their study area in Lopé National Park.  Lopé National Park is a good place to watch forest elephants.

“With forest elephants, you can only see them well in a clearing, or in a savanna,” Stephanie explains.  Forest elephants spend most of their time deep in the forest where people cannot see them.  The northeastern part of Lopé National Park is a patchwork of forest and savanna, so forest elephants are more visible there than in most of their range.  To identify the elephants, Stephanie and her team would drive around the park’s road network at sunrise and sunset and photograph every elephant that they saw.

Once they had a photo catalog of all of the individual elephants that they could find, they had to figure out ways to recognize each individual.  Savanna elephant researchers frequently identify the individual elephants that they study by the patterns of tears in their ears.  This method would not work for all forest elephants however.

“Most forest elephants in Lopé don’t have ear tears,” says Stephanie.  Instead she learned to identify her study elephants by their tusk shape and the vein patterns in their ears.  Stephanie eventually identified 117 individual elephants.

Once all of the individuals were identified, Stephanie looked at the observation data of which individuals formed groups and associated with other individuals.  As best as she could, she directly observed the social network of the forest elephants in Lopé National Park.

The Poop Tells All

Stephanie’s colleague scoops up some elephant poop. It contains DNA that can help scientists figure out how related elephants are to each other. Photo by Stephanie Schuttler.

Another challenge for the forest elephant study was determining how all of the elephants observed were related to each other.  Stephanie addressed this challenge by using genetic analysis of the elephant population.  Like every other animal, each individual elephant has a unique genetic pattern that makes it distinct from every other elephant.  Individuals that are closely related to each other will have genetic patterns that are more similar to each other than are the genetic patterns of unrelated individuals.

Stephanie collected genetic material for her genetics work from elephant dung.

Stephanie collects some poop. Photo by Stephanie Schuttler.

How-To Guide for collecting genetic samples from forest elephant dung:

  1. Watch forest elephant until it poops.  Wait for elephant to leave so that you can get to sample safely.
  2. Collect a small sample from the outside of the dung with a popsicle stick.
  3. Put it in a small tube and boil the tube to kill any potential germs.
  4. Add a chemical buffer to preserve the DNA (genetic material).

You might think that collecting genetic samples from elephant dung would be yucky and stinky, but it is not necessarily so.  “Forest elephants in Lopé eat fruits, leaves, bark, and grass, so their poop smells more like lawn mower clippings,” says Stephanie.

Once Stephanie had collected DNA from all of the elephants that she could get samples from she took them back to a genetics laboratory at the University of Missouri.  She used a technique called microsatellite analysis to look at the genetic pattern of each individual elephant.  Microsatellite patterns of closely related individuals like a mother and child will be similar and those of unrelated individuals will be quite different from each other.

What Stephanie Learned

Stephanie was surprised to find that forest elephants of the same matriline (meaning they shared their mothers’ ancestry) were found all over the park in different places.  But when looking at the social network, she found that they tended to associate with one another.  This finding fits in with what is known in savanna elephants, where closely related females and their female offspring will usually be found with each other for their entire lives.  Male savanna elephants will live with their mother, aunts, grandmother, and sisters until their teenage years (about 10 to15 years old) and then leave to live with other males or by themselves.

From her direct behavioral observations, Stephanie found that some individual forest elephants have few or no known associates that they hang out with.  Forest elephants were usually observed in small groups consisting of a mother and calf.  Sometime other adults were seen with a mother forest elephant and calf, but usually group size was not larger than five individuals.

Stephanie analyzed her behavioral observations using network analysis, a way of measuring how individuals in a population are connected to each other by looking at patterns of connections between the groups that they are in.

In savanna elephant populations, network analysis shows that almost every individual elephant in a savanna elephant social network is connected to every other individual because at some point their family units will interact with each other.

In contrast, network analysis of the forest elephants shows that the forest elephant social network is very patchy.  There are many gaps in connections between forest elephants, meaning that most forest elephant individuals are not meeting each other.  Stephanie observed the patchy nature of the forest elephant social network in both directly observed behavior and genetic patterns.

Although there are more observations of savanna elephants, there still appear to be large differences between the savanna and forest elephants and therefore more questions to explore about the forest elephant social network.

“We need to understand the differences between individuals who are more social and less social and how it affects survival and fitness,” says Stephanie.  “We need to understand how they interact with each other and what they need to survive.  They are very secretive.”  Do forest elephant mothers who associate with more individuals have better success in protecting their calves from predators or finding food? Do these mothers have more calves and are they less stressed, and healthier? These questions and many others about forest elephants remain to be answered.

How You Can Help Elephants

Forest elephants are listed as Vulnerable by the IUCN. This means there are many fewer than there used to be, and they are at risk of going extinct. In fact, while there used to be 700,000 forest elephants, scientists think there are only 100,000 left. Photo by Stephanie Schuttler.

One thing that is clear is that all elephant social networks in Africa, both savanna and forest elephants are in danger from humans.

“Poaching for ivory is the biggest danger,” says Stephanie.  She suggests several ways that anyone who is concerned about the future of elephants can help them survive:

  • Spread the word to your friends and family and across social media about not buying ivory. Explain how illegal hunting destroys elephant social networks that they need to survive.
  • Write to your governmental representatives to encourage them to help African nations fund anti-poaching activities and enforce laws against the illegal ivory trade.
  • Donate to conservation organizations who are supporting rangers and law enforcement on the ground in African nations in anti-poaching campaigns.

 

Stephanie’s study site. Photo by Stephanie Schuttler.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 










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