Although it is common knowledge that elephants eat plants, figuring out exactly what type of plants they consume is more challenging.
In a study led by Brown University, an international team of conservation biologists has recently used innovative methods to analyze the dietary habits of two groups of elephants in Kenya. This was done in an effort to precisely identify the specific types of plants individual members of the groups eat.
Better understanding the dietary preferences of individual elephants could help answer important questions about the foraging behaviors of various elephant groups. This could help experts devise better conservation approaches to keep elephants not only sated but satisfied.
“It’s really important for conservationists to keep in mind that when animals don’t get enough of the foods that they need, they may survive – but they may not prosper,” said senior author Tyler Kartzinel, an assistant professor of Environmental Studies and of Ecology, Evolution, and Organismal Biology at Brown.
“By better understanding what each individual eats, we can better manage iconic species like elephants, rhinos, and bison to ensure their populations can grow in sustainable ways.”
The experts used a cutting-edge genetic technique called DNA metabarcoding to identify the composition of biological samples by matching the DNA fragments representing an elephant’s diet to a library of plant DNA barcodes.
This is the first time this method has been used to answer pressing questions about social foraging ecology, i.e. how members of a social group (such as a family) decide what foods to consume.
“When I talk to non-ecologists, they are stunned to learn that we have never really had a clear picture of what all of these charismatic large mammals actually eat in nature,” Kartzinel said.
“The reason is that these animals are difficult and dangerous to observe from up-close, they move long distances, they feed at night and in thick bush, and a lot of the plants they feed on are quite small.” In addition, their food is also highly difficult to identify by visual observations alone, even by expert botanists.
By using a method called “stable isotope analysis,” which consists of chemical analyses of animal hair, previous research conducted two decades ago by two of the study authors – George Wittemyer from Colorado State University and Thure Cerling from the University of Utah – has found that elephants switch from eating fresh grasses during the rainy season to eating trees during the long dry season.
Although the researchers managed to discover broad-scale dietary patterns, they could not identify the different types of plants individual elephants eat.
Now, by using (still viable) fecal samples collected by Wittmeyer and Cerling 20 years ago, the scientists combined analyses of carbon stable isotopes from elephant hair and feces with DNA metabarcoding, GPS-tracking, and remote-sensing data to reliably pinpoint dietary variations of individual elephants in the two groups.
The analysis – which involved matching each unique DNA sequence in the sample to a collection of reference plants and comparing the diets of individual elephants through time – revealed that dietary differences among individuals were frequently far greater than had been previously assumed.
These surprising findings held even in the case of family members foraging together on a specific day. The results could also help address a classic paradox that wildlife ecologists struggled with for decades: given the fact that all elephants apparently eat the same types of plants, why isn’t competition for food pushing family groups apart and force them to forage independently?
According to Kartzinel, the answer could be that elephants vary their diets based not only on what is available, but also on their specific preferences and physiological needs.
For instance, a pregnant elephant may have different requirements and cravings at various times during her pregnancy. Thus, since individual elephants will not always eat exactly the same plants at the same time, there will usually be enough plants for all the members of a group.
This crucial discovery could have major implications for conservation biologists. It will provide them with insights into creating environments with a wide variety of plants in order to help elephants successfully reproduce and increase their populations.
At the same time, it will decrease the chances of inter-species competition and prevent animals from poaching human food sources, such as crops.
“Wildlife populations need access to diverse dietary resources to prosper. Each elephant needs variety, a little bit of spice — not literally in their food, but in their dietary habits,” Kartzinel concluded.
The study is published in the journal Royal Society Open Science.
Elephants, magnificent creatures known for their intelligence, strength, and memory, have been an integral part of our world’s rich biodiversity. However, their survival hangs in the balance due to human activities. Understanding their conservation status is essential to build effective strategies to protect them.
There are three recognized species of elephants: the African bush elephant, the African forest elephant, and the Asian elephant.
African bush elephants hold the title of the world’s largest land animal, while their forest counterparts and the Asian elephants are somewhat smaller. Their trunks, large ears, and long tusks are iconic features that set them apart. But these impressive physical traits are not merely for show.
Elephants use their trunks for various tasks, including feeding, drinking, and social interactions. Their large ears help dissipate heat, and the tusks, elongated incisor teeth, serve as tools for digging and weapons in fights.
Elephants are highly social creatures, with matriarchal family units at the core of their society. They live in a variety of habitats, from forests to deserts, provided there’s sufficient water and food. Elephants are herbivores, feeding on a diet that includes grass, bark, roots, and leaves.
However, their home ranges are shrinking dramatically due to human activities. Deforestation for agriculture, infrastructure development, and logging, coupled with the encroachment of human settlements, has resulted in significant habitat loss for these giants.
Sadly, all three species of elephants face severe threats that have led to their classification as vulnerable or endangered by the International Union for Conservation of Nature (IUCN).
The African bush elephant, once widespread across Africa, is now listed as ‘Endangered.’ Their population has seen a steep decline, driven primarily by poaching for ivory and habitat loss.
The African forest elephant’s situation is even more alarming. Classified as ‘Critically Endangered,’ they suffer heavy losses from both habitat loss, due to extensive logging and mining activities, and ivory poaching.
The Asian elephant, with its habitat ranging from India to Southeast Asia, faces similar challenges and is classified as ‘Endangered.’ Apart from habitat loss and human-elephant conflicts, the capture of wild elephants for tourism and entertainment purposes also contributes to their population decline.
Recognizing the urgency of the situation, various global and local organizations are intensifying their conservation efforts. Key strategies include habitat preservation, anti-poaching initiatives, and policymaking to mitigate human-elephant conflicts.
Protected areas like national parks and wildlife reserves are crucial to ensure safe habitats for elephants. Anti-poaching laws and enforcement need to be stringent, as illegal hunting for ivory remains a major threat.
The international trade in ivory, banned by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), requires continuous monitoring and regulation.
In regions where elephants and humans coexist closely, the implementation of conflict mitigation measures is crucial. This includes building fences around agricultural lands, creating early warning systems, and educating communities about living harmoniously with elephants.
Lastly, captive elephant welfare needs attention. Stricter regulations should ensure ethical treatment, and the phase-out of elephants from exploitative practices in tourism and entertainment should be promoted.
Elephants are not just iconic wildlife; they are also ‘keystone’ species that help maintain the health and diversity of ecosystems. Their conservation is not a matter of choice but an absolute necessity.
We have a collective responsibility to ensure these magnificent animals continue to roam our planet freely, just as nature intended.