Mathematicians at the University of California, Merced created a model of penguin huddles that assumes each penguin aims solely to minimize its own heat loss. Surprisingly, the model reveals that such self-centered behavior results in an equitable sharing of heat. The results are published in the online journal PLOS ONE and the researchers will discuss their findings at the annual meeting of the American Physical Society's (APS) Division of Fluid Dynamics (DFD), held Nov. 18 – 20 in San Diego, Calif.
Penguins aren't a typical study subject for Francois Blanchette, an applied mathematician at UC Merced who focuses on fluid dynamics. However, after seeing penguin huddles in the movie "The March of the Penguins" Blanchette realized that the important factors that shaped the huddle, including wind and heat flow, fell within his area of expertise.
Blanchette and his fellow researchers, Arnold Kim and Aaron Waters, modeled huddles packed so tightly that only the penguins on the outside could move. Each penguin in the huddle generated heat that the wind blew away. By considering such factors as the number of penguins in the huddle and the strength and turbulence of the wind, the model calculated which penguin on the outside of the huddle was coldest. The coldest penguin moved to the most sheltered spot available, usually relocating from a windward to a leeward position, and then the heat distribution around the huddle was recalculated. Repeated iterations showed the huddle gradually elongating and creeping downwind over time.
At first the model assumed perfectly steady wind patterns and identical penguins, but produced huddle shapes that were longer and thinner than those observed in nature. When the researchers added uncertainty, which could represent irregular wind eddies and natural differences in the size and cold tolerance of individual penguins, the modeled huddles closely matched real huddles.
The researchers were surprised the model showed the penguins shared warmth nearly equally among themselves. "Even if penguins are only selfish, only trying to find the best spot for themselves and not thinking about their community, there is still equality in the amount of time that each penguin spends exposed to the wind," says Blanchette. Not all instances of selfish behavior result in such fair outcomes, he notes. "A penguin huddle is a self-sufficient system in which the animals rely on each other for shelter, and I think that is what makes it fair. If you have some kind of obstacle, like a wall, then I think it would stop being fair," Blanchette says.
Currently the researchers would like feedback from biologists before they further refine the model. Gathering experimental data, however, is difficult. "Penguins huddle during blizzards, when the conditions are horrible, and if you're going to collect data you're also going to be in a blizzard in horrible conditions," Blanchette points out. The mathematicians hope their work might serve as a guide for scientists in the field, helping them to know which observations to make to test the model.
Blanchette says his group may also investigate how to adapt the model to describe other biological organisms, such as certain bacteria, that move as a group in response to an outside stimulus like food or the presence of a toxin. Eventually, concepts from the model may guide the design of swarming robots that shelter each other in harsh conditions. But for now Blanchette is enjoying a more immediate side benefit of the research: "Nearly everybody seems to love penguins and not enough people love math," he says. "If we use math to study penguins we could potentially teach more people to love math too!"
Paper: "Modeling huddling penguins" is published in PLOS ONE at 5:00 p.m. on Friday, Nov. 16. Link: http://dx.plos.org/10.1371/journal.pone.0050277
Presentation: "Modeling huddling penguins" is at 10:56 a.m. on Monday, Nov. 19 in room 28A. Abstract: http://meeting.aps.org/Meeting/DFD12/Event/178234MORE MEETING INFORMATION
Selected entries from the Gallery of Fluid Motion will be hosted as part of the Fluid Dynamics Virtual Press Room. In mid-November, when the Virtual Press Room is launched, another announcement will be sent out.
This release was prepared by the American Institute of Physics (AIP) on behalf of the American Physical Society's (APS) Division of Fluid Dynamics (DFD).ABOUT THE APS DIVISION OF FLUID DYNAMICS
Charles Blue | EurekAlert!
Earthlike 'Star Wars' Tatooines May Be Common
31.03.2015 | University of Utah
Dusty substructure in a galaxy far far away
31.03.2015 | Max-Planck-Institut für Astrophysik
In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...
The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.
As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...
When an earthquake hits, the faster first responders can get to an impacted area, the more likely infrastructure--and lives--can be saved.
The Atlantic overturning is one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards. Also known as the Gulf Stream system, it is responsible for the mild climate in northwestern Europe.
Scientists now found evidence for a slowdown of the overturning – multiple lines of observation suggest that in recent decades, the current system has been...
Because they are regularly subjected to heavy vehicle traffic, emissions, moisture and salt, above- and underground parking garages, as well as bridges, frequently experience large areas of corrosion. Most inspection systems to date have only been capable of inspecting smaller surface areas.
From April 13 to April 17 at the Hannover Messe (hall 2, exhibit booth C16), engineers from the Fraunhofer Institute for Nondestructive Testing IZFP will be...
25.03.2015 | Event News
19.03.2015 | Event News
17.03.2015 | Event News
31.03.2015 | Life Sciences
31.03.2015 | Materials Sciences
31.03.2015 | Earth Sciences