New research shows dinosaur dung fertilizes planet

October 17, 2017, Northern Arizona University
Alamosaurus dinosaur. Credit: Northern Arizona University

Whether it started with exhibits at the Natural History Museum or fun-terrified screams watching Jurassic Park, humans have always been awestruck by dinosaurs.

But little is known about what, if any, role dinosaurs and other like mammoths or elephants play in ecosystem functioning. What would the world be like if they never existed?

Christopher Doughty, faculty member in the School of Informatics, Computing and Cyber Systems at Northern Arizona University, asks that question often. He has been studying large animals for more than 10 years, specifically how these animals have increased the planet's fertility.

"Theory suggests that large animals are disproportionately important to the spread of fertility across the planet," Doughty said. "What better way to test this than to compare fertility in the world during the Cretaceous period—where sauropods, the largest herbivores to exist, roamed freely—to the Carboniferous period—a time in Earth's history before four-legged herbivores evolved."

During these two periods, were buried faster than they could decompose. As a result, coal was formed. Doughty gathered coal samples from mines throughout the U.S. By measuring the coal elemental concentrations, he found elements needed by plants, like phosphorus, were more abundant and much better distributed during the era of the dinosaurs than the Carboniferous. The data also revealed that elements not needed by plants and animals, such as aluminum, showed no difference, suggesting the herbivores contributed to increased global fertility.

According to Doughty, these large animals are important not for the quantity of dung they produce, but for their ability to move long distances across landscapes, effectively mixing the nutrients. By increasing the abundance and distribution of elements like phosphorus, plants grow faster, meaning are responsible for producing their own food and contributing to their lush habitats.

But as today's large animal populations become more in danger of extinction, the environment too is at risk. Simply put, fewer large animals may mean less plant growth.

"This is important for two reasons," Doughty said. "First, we are rapidly losing our remaining large animals, like forest elephants, and this loss will critically impair the future functioning of these ecosystems by reducing their fertility. Second, combining the idea that large are disproportionately important for the spread of nutrients with the natural rule that animal size increases over time, means the planet may have a Gaia-like mechanism of increasing fertility over time.

Life makes the planet easier for more life."

Explore further: Extinctions of large animals sever the Earth's 'nutrient arteries' (Update)

Related Stories

Animals in Africa 1000 years ago

November 30, 2015

A team of local scientists have wound back the clock by 1000 years to reconstruct wildlife populations across Africa to help us better understand how they have shaped the world we live in.

How I found the world's oldest communal dinosaur toilet

December 19, 2013

Fossils can tell us lots about animals – their size, age or sex, which is mostly physical characteristics. Evidence about how they may have behaved is rare. But the 240m-year-old fossil dung that I found, along with my ...

Animals, not drought, shaped our ancestors' environment

June 26, 2017

The shores of Lake Turkana, in Kenya, are dry and inhospitable, with grasses as the dominant plant type. It hasn't always been that way. Over the last four million years, the Omo-Turkana basin has seen a range of climates ...

Recommended for you

Plant characteristics shaped by parental conflict

November 20, 2018

Different subpopulations of a plant species can have distinct traits, varying in size, seed count, coloration, and so on. The primary source of this variation is genes: different versions of a gene can lead to different traits. ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.