The Cretaceous bird Jeholornis pooping out seeds from fruit, helping fruit-bearing plants take over the world. Illustration by Zhixin Han and Yifan Wang.
Key Points:
- The Jeholornis, a prehistoric bird from the Cretaceous Period, is determined to have been the first fruit-eating animal.
- It is believed the birds helped fruit-bearing plants spread by dispersing seeds in their feces across ecosystems.
- The fruit-bearing plants, in turn, likely affected the Jeholornis’s evolution in helping it develop features that allowed them to fly in order to find fruits to eat.
Plants and animals have a long history of coevolution. Flowering plants and bees, for instance, have evolved over time to contribute to each other’s propagation. A recent study published in eLife proposes that a certain prehistoric bird and fruit-bearing plants share a similar relationship.
After examining bird fossils and the contents of their stomachs, researchers concluded that the Jeholornis, a Mezosoic bird that populated China during the Cretaceous Period about 120 million years ago, was the first animal to eat fruits. Researchers theorize the birds may have helped the plants proliferate by consuming their fruits, and then dispersing their seeds in other locations.
“Birds are important consumers of fruit today, and play important roles in seed dispersal, but so far there has not been direct evidence of fruit consumption by early birds, outside the bird crown group,” said Han Hu, a researcher at Oxford University and the study’s first author. “This obstructs our understanding of the origins of this important plant-animal interaction.”
Initially, scientists hypothesized that the Jeholornis consumed only seeds. It was not until later that scientists postulated the birds may have instead eaten fruit that contained seeds. Consuming fruit and then scattering whole seeds would likely benefit the genetic advancement of those plants. Eating the seeds, and digesting them before passing the material, on the other hand, would not have proven beneficial.
Clues about the Jeholornis’s mandible helped the researchers determine that the birds likely ate whole fruits. They also discovered that some Jeholornis birds had gizzards, which seed-eating birds use to crush seeds as they pass through the digestive tract. These findings led the researchers to conclude that the birds’ diet was seasonal, meaning they ate fruit when it was in season, and consumed seeds when fruit was not available.
In addition, the researchers believe that feasting on fruits may have affected how the Jeholornis evolved a long tail, which would have allowed it to navigate from tree to tree.
They hope their findings will motivate scientists to answer other evolutionary questions, thereby leading to a better understanding about the lives of other extinct animals.