Elephants have diverse diets, just like humans

Individual elephants' diets revealed by DNA metabarcoding.


Similar to humans, elephants exhibit variations in their dietary preferences. Understanding the specific types of plants consumed by elephants is crucial for biologists and conservationists in developing effective conservation strategies.

Researchers from Brown University conducted a study in Kenya to analyze the dietary habits of elephants using innovative methods. The study provided precise information on the types of plants consumed by individual elephants within two groups. The findings help address questions about group foraging behaviors and assist biologists in implementing effective conservation strategies for elephant populations.

Tyler Kartzinel, an assistant professor of environmental studies and ecology, evolution, and organismal biology at Brown, said, “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. By better understanding what each individual eats, we can better manage iconic species like elephants, rhinos, and bison to ensure their populations grow sustainably.”

The scientists utilized DNA metabarcoding, a state-of-the-art genetic technique, as a primary tool in their study. This method involves matching extracted DNA fragments from elephant food samples to a library of plant DNA barcodes, enabling researchers to identify the specific plant composition. Brown University has been actively developing applications for this technology, combining expertise from molecular biology and computational fields to address conservation challenges field researchers face.

In a groundbreaking achievement, researchers utilized DNA metabarcoding to address a long-standing question regarding social foraging ecology. This technique allowed them to investigate how social group members, such as family members, make food choices.

Traditionally, gaining a clear understanding of the dietary habits of large mammals, like elephants, has been challenging due to factors such as the animals’ elusive nature, nocturnal feeding habits, long-distance movements, and the difficulty of identifying their food plants visually. Even expert botanists struggle to identify the plants consumed by elephants. This study marks the first application of DNA metabarcoding in unraveling the dietary preferences of these charismatic mammals in their natural habitat.

The research team compared DNA metabarcoding, a new genetic technique, with stable isotope analysis, a chemical analysis of animal hair. Previous studies by George Wittemyer and Thure Cerling revealed that elephants alter their diet from fresh grasses to trees during the dry season. While stable isotope analysis provided broad dietary patterns, it couldn’t identify specific plant types.

The team utilized fecal samples collected almost 20 years ago, which were still viable for analysis, from a collaboration with Save the Elephants. A study author, Brian Gill, determined their usability despite years of storage.

DNA metabarcoding was employed to investigate the foraging history of individual elephants. This advanced genetic technique allowed researchers to analyze the DNA fragments extracted from elephant food samples, providing insights into the specific plants consumed by each elephant. By utilizing DNA metabarcoding, the study aimed to understand the individual foraging preferences and behaviors of elephants, contributing to a comprehensive understanding of their dietary habits.

Journal Reference:

  1. Brian A. Gill, George Wittemyer, et al., Foraging history of individual elephants using DNA metabarcoding. Royal Society Open Science. DOI: 10.1098/rsos.230337.