Elephant Teeth Tell a Story of Survival and Adaptation in a Changing World

Elephants hace adapted to their herbivorous diet and can grow their teeth up to 30 centimeters in length.

They have six sets of molars that replace each other throughout their lives, and each molar has multiple ridges that help them grind tough plant materials.

But how did elephants evolve such specialized teeth? And what factors influenced their evolution?

A new study by researchers from the University of Helsinki sheds some light on these questions by examining the fossil teeth of proboscideans, the group of mammals that includes elephants and their extinct relatives.

The study revealed how proboscidean teeth evolved in response to long term changes in diet and climate in Africa during the last 26 million years.

How diet and climate shaped proboscidean teeth

(Photo : SAI AUNG MAIN/AFP via Getty Images)

The researchers analyzed the carbon and oxygen isotopes in the enamel of more than 300 fossil teeth of different proboscidean species from East Africa.

These isotopes can provide information about the type of plants that the animals ate and the climatic conditions that they lived in.

The researchers also measured the crown height and the number of ridges on the molars, which are indicators of tooth wear and adaptation to different diets.

The results showed that proboscidean teeth evolved in two main phases.

The first phase occurred between 23 and 11 million years ago, when some proboscideans, such as choerolophodonts, started to feed more on grasses, which are rich in silica and cause more tooth wear than other plants.

This shift was associated with local changes in vegetation due to tectonic uplift and volcanic activity in East Africa, which created more open and grassy habitats.

However, the teeth of these proboscideans did not change much in morphology, as they were able to cope with moderate tooth wear by changing their behavior and feeding selectively on less abrasive parts of grasses.

The second phase occurred between 10 and 2 million years ago, when true elephants (elephantids) evolved high-crowned and multi-ridged molars that were better suited for feeding on grasses.

This phase was associated with global changes in climate that caused more arid and seasonal conditions in East Africa, which favored the expansion of grasslands over forests.

The teeth of these elephants also underwent rapid evolutionary bursts during periods of extreme climatic drying, such as around 4 and 2 million years ago, when the crown height and the number of ridges increased significantly.

These evolutionary changes did not reverse during periods of less harsh climatic conditions, suggesting that they were irreversible adaptations to cope with high tooth wear.

Also Read: Scientists to Bring Extinct Woolly Mammoths Back to Life by Creating 'Arctic Elephant'

Why proboscidean teeth matter for understanding evolution and ecology

The study demonstrated that proboscidean teeth are valuable sources of information for understanding how animals adapt to changing environments over long time scales.

By combining isotopic and morphological data, the researchers were able to reconstruct the dietary and climatic history of proboscideans in East Africa, and reveal how different factors influenced their evolution.

The study also has implications for understanding the role of proboscideans in shaping their ecosystems.

Proboscideans are keystone species that affect the structure and composition of vegetation through their feeding and trampling activities.

By tracing the evolution of their teeth, the researchers were able to infer how proboscideans interacted with different types of plants over time, and how they influenced the diversity and distribution of other herbivorous mammals.

The study also highlights the importance of conserving elephants and their habitats today.

Elephants are endangered species that face multiple threats from poaching, habitat loss, and human-wildlife conflict.

By studying their ancient relatives, the researchers hope to raise awareness about the evolutionary and ecological significance of elephants, and inspire more efforts to protect them.