Evolution of Bat Teeth and Jaws – Latest Study

Bhumika Goel / October 2023

Introduction

The bats have similar evolutionary stories to tell unlike human beings, and they’re much more extensive. There are more than 200 species of noctinoid bats in the American Tropics. Despite their closeness to one another, the jaws had evolved in extraordinarily different shapes and sizes to exploit various food sources. These adaptations include dramatic, but also consistent, changes in the number, size, shape, and position of teeth, according to a study published in Nature Communications on August 22.

For instance, the bats with short snouts don’t have any teeth. Lack of space may be the reason for teeth absenteeism. The animals with longer jaws have room for more teeth, unlike humans. And their total tooth supply is closer to that of the ancestors of placental mammals. The research team behind this study believes that by comparing noctillan species, the history of the evolution of mammals’ faces, especially their jaws and teeth, would be easier to understand.

The Research Findings

“They have all four tooth types—incisors, canines, premolars, and molars—just like humans do,” added coauthor Sharlene Santana, a University of Washington biology professor and the Burke Museum of Natural History and Culture’s mammal curator. “And noctylonoid bats have evolved a wide variety of food in less than 25 million years, and the time needed for these adaptations to take hold is very brief.”

 “Noctilinoid species with short faces, such as bulldogs, have strong jaw to bite the tough exterior of fruits they eat.” Some species have long snouts to obtain flower nectar. What is it about this diversity that has developed so quickly? Lead author Alexa Sadier, an incoming professor at the Institute of Evolutionary Sciences of Montpellier, France, said, “What must have changed in their mouths and teeth to make it possible?” He was a postdoctoral fellow at the University of California, Los Angeles when he started this project. Scientists are not sure why this surge of diet change took place among the bats. Today, however, several noctilionoid species feast on insects, fruits, nectars, fish, and even blood. Vampire bats also make a part of this group.

The team studied the shapes and sizes of teeth, premolars, and molars in over 100 noctilionoid species using CT scans and other methods. This study was on the bats collected from museum specimens and wildlife. To determine the different phases of teeth and jaw development, the researchers compared relative tooth size and other cranial characteristics of species with different diets using mathematical models.

The researchers found that certain noctinoid bats develop the proper number of teeth as part of their diet, resulting in grins, because of some developmental rules. For instance, bats with long jaws, such as those that feed on nectar, or intermediate jaws, such as those that eat a lot of insects, typically had three premolars and three molars on each side of their jaws. However, a cloud of fruit-eating bats and other bats with short jaws tend to lose either or both of their back molars. 

You can have more teeth when you have more room,” Sadier remarked. “But even though they have a stronger bite, you just run out of room for all these teeth in bats with shorter stature.”

According to Sadier, “the first teeth to erupt tend to grow bigger since there is not enough space for the subsequent teeth to emerge.”

“We have the chance to test some of the theories regarding the regulation of tooth growth, shape, and size in mammals thanks to this project,” Santana said. “Remarkably, little is known about the evolution of these crucial structures!”

Mice with exclusively molar teeth and significantly altered incisors are studied to understand the development of mammalian teeth. The question of whether the genes and developmental patterns that regulate the growth of teeth in mice also affect mammals with more “ancestral” sets of teeth, such as humans and bats, remains unanswered by scientists.

Along with many other unanswered questions about how evolution shapes mammalian features, Sadier, Santana, and their colleagues think their ongoing project can begin to answer these questions in bats. The researchers are broadening the scope of their research to include noctilionoid canines and incisors to learn more about the genetic and developmental processes governing tooth development in this varied group of bats.

“These bats are subject to such strong selection pressures that their shapes must closely match their functions,” Santana said. “I believe these species still hold a great evolutionary mystery.”

The study coauthors include 

1. Robert Haase, Researcher at the Dresden University of Technology, Germany
2. Andrew Krause, Assistant Professor at Durham University, United Kingdom
3. Renaud Dessalles, Mathematician with Green Shield Technology
4. Michael Lake, Research scientist at UCLA
5. Laurent Bentolila, Research scientist at UCLA
6. Natalie Nieves, Research scientist at UCLA
7. Karen Sears, Professor at UCLA. 
8. Neal Anthwal, Research Associate at King’s College London. 

The National Science Foundation is providing funding for this research.

Conclusion

The study of the development of mammals’ faces has, in conclusion, provided invaluable insight into the diversity of life on Earth. Recent advances in Genomics, Paleontology, and Development Biology have successfully illustrated the extraordinary changes over millions of years. These studies have not only improved our understanding of the intricate processes that shape facial structure, but they also shed light on its adaptive significance.
As we continue to discover fascinating tales hidden in their constantly evolving faces, these documents remind us of the importance of protecting mammalian diversity. This knowledge is not only improving our appreciation of the natural world but also bringing practical implications for areas like medicine and genetics, emphasizing the importance of research in this area.

Bhumika Goel is a technology and design thinker, a lifelong learner having a wide range of experience across WordPress development, content marketing and search engine optimization. Creative web applications, tools, and products that your customers will love and get you real business results, is something she can empower you with. She is passionate for delivering high-quality work that meets the needs and expectations of her clients. She is always eager to learn new skills and technologies to enhance her portfolio and stay ahead of the curve. She is looking for new opportunities to collaborate with other professionals and help businesses grow their online presence and reach their goals.