Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rudolph the red-nosed reindeer's cooling strategy revealed

27.10.2011
How exercising reindeer keep cool

Insulated in a luxuriously thick winter coat, reindeer are perfectly prepared for the gripping cold of an Arctic winter.

But the pelt doesn't just keep the cold out, it keeps the warmth in too: which is fine when the animals are resting, but what happens when they are active and generating heat? Usain Bolt would never sprint in a fur coat so how do exercising reindeer avoid overheating? Arnoldus Blix from the University of Tromsø, Norway, explains that the animals have three tactics: panting with their mouths closed to evaporate water from the nose; panting with the mouth open to evaporate water from the tongue; and activating a cooling system that selectively cools the blood supply to the brain. But how do they coordinate these different strategies for protection? Intrigued, Blix and his colleagues Lars Walløe from the University of Oslo, Norway, and Lars Folkow, also from Tromsø, decided to monitor reindeer brain temperatures, breathing rates and the blood flow through several major blood vessels in the head, to find out how active reindeer keep cool in winter.

The team publish their discovery that reindeer use three strategies to keep cool and only resort cooling their brains with a heat exchanger when their temperature becomes dangerously high in The Journal of Experimental Biology at http://jeb.biologists.org.

'Reindeer are the best animals to work with; once they trust the trainer they will do anything for you,' explains Blix. So, the team trained reindeer to trot at 9km/h on a treadmill in temperatures from 10 to 30°C to get the animals warmed up while they recorded the animals' physiological responses. In the early stages of the run their breath rate rocketed from 7breaths/min to an impressive 260breaths/min. Blix explains that the animals were inhaling chilly air through their noses and evaporating water from the mucous membranes to cool blood in the nasal sinuses before sending it back to the rest of the body through the jugular vein to keep their temperature down.

However, as the animals continued exercising and generating more heat, they switched to panting, throwing their mouths wide open and flopping their tongues out like dogs. 'The tongue is large, vascularised and well circulated,' explains Blix, and adds, 'They moisturise the tongue so you have evaporation which also takes heat away from the blood'.

Monitoring the temperature of the reindeer's brain, the team noticed that the blood flow through the animal's cooling tongue peaked when the brain's temperature reached a critically high 39°C, at which point the reindeer switched to their third tactic. They began selectively cooling the brain by diverting cooled venous blood – which came from the nose – away from the body and up into the head, where it entered a network of heat exchanging blood vessels to cool the hot arterial blood destined for the brain to protect it from overheating.

Blix admits that initially he had not thought that this strategy would work. 'Only 2% of the respiratory volume went through the nose when they resorted to open mouth panting,' he says. However, when he calculated the colossal amounts of air inhaled by the exercising animals – coupled with the low air temperatures – it was clear that the reindeers were able to inhale sufficient cold air through their noses to keep their brains cool, but only as a last resort once the other cooling tactics were no longer sufficient.

So Blix and his colleagues have discovered how heavily insulated reindeer prevent themselves from overheating and how Rudolph keeps cool every Christmas Eve.

IF REPORTING ON THIS STORY, PLEASE MENTION THE JOURNAL OF EXPERIMENTAL BIOLOGY AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO: http://jeb.biologists.org

REFERENCE: Blix, A. S., Walløe, L. and Folkow, L. P. (2011) Regulation of brain temperature in winter-acclimatized reindeer under heat stress. J. Exp. Biol. 214, 3850-3856.

This article is posted on this site to give advance access to other authorised media who may wish to report on this story. Full attribution is required, and if reporting online a link to jeb.biologists.com is also required. The story posted here is COPYRIGHTED. Therefore advance permission is required before any and every reproduction of each article in full. PLEASE CONTACT permissions@biologists.com

Sue Chamberlain | EurekAlert!
Further information:
http://www.biologists.org
http://jeb.biologists.org

More articles from Life Sciences:

nachricht The world's tiniest first responders
21.06.2018 | University of Southern California

nachricht A new toxin in Cholera bacteria discovered by scientists in Umeå
21.06.2018 | Schwedischer Forschungsrat - The Swedish Research Council

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Better model of water under extreme conditions could aid understanding of Earth's mantle

21.06.2018 | Earth Sciences

What are the effects of coral reef marine protected areas?

21.06.2018 | Life Sciences

The Janus head of the South Asian monsoon

21.06.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>