Navigation Links
Rudolph the red-nosed reindeer's cooling strategy revealed
Date:10/26/2011

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 Troms, 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 Walle from the University of Oslo, Norway, and Lars Folkow, also from Troms, 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 30C 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 39C, 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.


'/>"/>

Contact: Sue Chamberlain
jeb@biologists.org
44-122-342-5525
The Company of Biologists
Source:Eurekalert

Related biology news :

1. Back off, Rudolph: Protecting this years Christmas tree crop
2. Albedo effect in forest disturbances can cause added warming, bonus cooling
3. Reforestations cooling influence -- a result of farmers past choices
4. Significant role of oceans in onset of ancient global cooling
5. Pitt study finds green water treatments may not kill bacteria in large building cooling systems
6. Signs of reversal of Arctic cooling in some areas
7. Hydrocooling shows promise for reducing strawberry weight loss, bruising
8. Cantabrian cornice has experienced seven cooling and warming phases over past 41,000 years
9. CO2 drop and global cooling caused Antarctic glacier to form
10. Decline of carbon-dioxide-gobbling plankton coincided with ancient global cooling
11. Powerful antibody-based strategy suggests a new therapeutic approach to diabetes and obesity
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/2/2016)... 2, 2016   The Weather Company , an IBM ... an industry-first capability in which consumers will be able to ... ask questions via voice or text and receive relevant information ... Marketers have long sought an advertising solution that ... be personal, relevant and valuable; and can scale across millions ...
(Date:5/20/2016)... May 20, 2016  VoiceIt is excited to ... VoicePass. By working together, VoiceIt and ... VoiceIt and VoicePass take slightly different approaches to ... both security and usability. ... this new partnership. "This marketing and ...
(Date:5/3/2016)... VILNIUS, Lithuania , May 3, 2016 /PRNewswire/ ... today released the MegaMatcher Automated Biometric Identification ... deployment of large-scale multi-biometric projects. MegaMatcher ABIS can ... and accuracy using any combination of fingerprint, face ... of MegaMatcher SDK and MegaMatcher ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... TORONTO , June 23, 2016 /PRNewswire/ - ... Ontario biotechnology company, Propellon ... the development and commercialization of a portfolio of ... cancers. Epigenetic targets such as WDR5 represent an ... contribute significantly in precision medicine for cancer patients. ...
(Date:6/23/2016)...  The Biodesign Challenge (BDC), a university competition that ... living systems and biotechnology, announced its winning teams at ... New York City . The teams, ... at MoMA,s Celeste Bartos Theater during the daylong summit. ... curator of architecture and design, and Suzanne Lee ...
(Date:6/23/2016)... 23, 2016 Apellis Pharmaceuticals, Inc. today ... trials of its complement C3 inhibitor, APL-2. The ... ascending dose studies designed to assess the safety, ... injection in healthy adult volunteers. Forty ... a single dose (ranging from 45 to 1,440mg) ...
(Date:6/23/2016)... Pleasant Prairie, WI (PRWEB) , ... June 23, ... ... sciences consultancy focused on quality, regulatory and technical consulting, provides a free ... webinar is presented on July 13, 2016 at 12pm CT at no charge. ...
Breaking Biology Technology: