You probably hadn't noticed -- but the head shape and overall size of rodents has been changing over the past century. A University of Illinois at Chicago ecologist has tied these changes to human population density and climate change.
The finding is reported by Oliver Pergams, UIC research assistant professor of biological sciences, in the July 31 issue of PLoS One.
Pergams said that such size-and-shape changes in mammals, occurring around the world in less than a century, are quite substantial.
He had done earlier studies on a century's worth of anatomic changes between two geographically isolated rodents -- Channel Island deer mice from coastal California and white-footed mice northwest of Chicago -- and noted fast change among both.
"I suspected they weren't unique examples," he said. "I wondered whether these changes were occurring elsewhere, whether they were global in nature, and what some of the causes may be."
Pergams examined specimen rodents from museums around the world, including the big collections held at Chicago's Field Museum and the Smithsonian in Washington. Altogether, he recorded more than 17,000 body and skull measurements from 1,300 specimens from 22 locations in Africa, the Americas and Asia. The animals were collected from 1892 to 2001, and Pergams compared those from before 1950 to those collected after.
He also compared specimens gathered from sparsely populated islands to those from the mainland, where human populations were denser.
Pergams found both increases and decreases in the 15 anatomic traits he measured, with changes as great as 50 percent over 80 years. Ten of the 15 traits were associated with changes in human population density, current temperature, or trends in temperature and precipitation.
"Rapid change, contrary to previous opinion, really seems to be happening quite frequently in a number of locations around the world," Pergams said. "There seem to be significant correlations with 'people-caused' parameters, such as population density and anthropologically-caused climate change."
While Pergams' study was by no means comprehensive, it was the first attempt of its kind to examine data on mammals from many global locations to find links between morphological change and variables such as population density and changing climate.
"Species can adapt quickly to rapid environmental changes -- quicker than many people have thought, especially for mammals," said Pergams. "Those mammals that can adapt quickly have a much higher chance to survive big environmental changes caused by humans. Understanding which species and populations have the greatest ability to change has a crucial impact on being able to conserve biodiversity."
The research was funded through a grant from the National Science Foundation and The Nature Conservancy. Climate change at various locations was tracked by Joshua Lawler of the University of Washington, who is co-author of the study.
An MP3 podcast on this subject is available at:
Paul Francuch | Newswise Science News
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology