HFMO
  • Main
    • News
    • Education, Ecology, and Conservation
    • Ecological Rules and Processes
    • Tips, Opinions, and Advice
    • Conservation Initiatives
    • Wildlife Profile
    • Social Media
    • Opportunities
    • Recent Activity
  • Diaries
  • Pictures and Videos
  • Bat Media
  • Resources
    • Blogs, and Magazines
    • Photography - Photographers, Grants, and Competitions
    • Scientific Societies, Charities, and NGOs
    • Interesting Talks
    • Suggested Readings, and Movies
    • R: code and packages
    • Public Datasets
    • E-mail Lists, and Sites for Job Opportunities
    • Funding Sources
  • Research
  • About me
  • Support us
  • Contact

Allen's rule

28/4/2019

0 Comments

 
    It is an ecogeographical rule formulated by Joel Asaph Allen in 1877 stating that animals that are adapted to colder climates tend to have shorter limbs and body appendages in comparison to animals that are adapted to more warm climates. It predicts that the body surface area-to-volume ratio of endotherimc animals (mammals and birds) tends to vary with the average temperature in which they occur (lower ratios in colder climates and higher ratios in hotter climates).  
     One of the main explanations for the theory is that endothermic animals in colder climates need to save as much energy as possible in the form of heat. Thus, the decreasing the surface area helps to avoid dissipating heat. Shorter body appendages and limbs also help to avoid heat loss as body extremities are some of the main body parts where animals exchange heat with the environment mainly due to heat exchange with the blood vessels close to the skin. Thus, having shorter ones help to decrease heat loss.

     One of the most classical examples of the Allen's rule is the correlation between ear length and air temperature for hares (genus Lepus) and foxes. However, some studies have showed that this rule might oversimplify too much.  
Picture

- From right to left the climate tend to be increasingly colder.

​
References
Feldhamer, G. A., Drickamer, L. C., Vessey, S. H., Merritt, J. F., & Krajewski, C. (2007). Mammalogy: adaptation, diversity, ecology. JHU press.

0 Comments



Leave a Reply.

    Picture

    Author

    Hernani has passion for wildlife, conservation, travelling and connecting with people

    “I wish it need not have happened in my time," said Frodo.
    "So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us.” 

    ― J.R.R. Tolkien, The Fellowship of the Ring

    Archives

    April 2019
    January 2019
    June 2018
    May 2018

    Categories

    All

    RSS Feed

Proudly powered by Weebly
  • Main
    • News
    • Education, Ecology, and Conservation
    • Ecological Rules and Processes
    • Tips, Opinions, and Advice
    • Conservation Initiatives
    • Wildlife Profile
    • Social Media
    • Opportunities
    • Recent Activity
  • Diaries
  • Pictures and Videos
  • Bat Media
  • Resources
    • Blogs, and Magazines
    • Photography - Photographers, Grants, and Competitions
    • Scientific Societies, Charities, and NGOs
    • Interesting Talks
    • Suggested Readings, and Movies
    • R: code and packages
    • Public Datasets
    • E-mail Lists, and Sites for Job Opportunities
    • Funding Sources
  • Research
  • About me
  • Support us
  • Contact