Winning by a neck -- Giraffes avoid competing with shorter browsers

The giraffe's elongated neck has long been used in textbooks as an illustration of evolution by natural selection, but this common example has received very little experimental attention. In the January issue of the American Naturalist, researchers at the Mammal Research Institute in the Department of Zoology and Entomology at the University of Pretoria tested whether foraging competition with shorter herbivores could explain why giraffes feed mostly on leaves high in trees, despite being able to feed at lower levels as well.

"This [study] provides the first real experimental evidence that the long neck of the giraffe might have evolved as a consequence of competition, which provides support for a previously untested textbook example of natural selection," says Elissa Cameron (University of Pretoria), who coauthored the study with Johan du Toit (University of Pretoria and Utah State University).

Giraffes are well known for their unusual height, and they generally feed high in the tree canopy, above the height other herbivores can reach. Giraffes receive more leaves per bite by foraging high in the tree, but it's unclear whether this is caused by competition -- smaller browsers eating some of the leaves at lower heights -- or if more leaves grow at higher levels.

The researchers built low fences around trees in greater Kruger National Park to stop smaller browsers from eating leaves. After a complete growing season they found that the number of leaves on the fenced trees was roughly the same, revealing that small browsers are responsible for most of the foraging. Therefore, the researchers argue, it is competition from other herbivores, such as kudu, that appears to drive giraffes to eat leaves high in the trees.


Contact: Patricia Morse
University of Chicago Press Journals

Page: 1

Related biology news :

1. Winning the oil endgame in America to be discussed at NJIT forum
2. Desertification: UN experts prescribe global policy overhaul to avoid looming mass migrations
3. The eyes have it! How box jellyfish avoid banging into things
4. Embryonic selection of sex avoids conceiving blind children
5. How to avoid a bat
6. Define precautionary principle to avoid clashes over biotechnology under World Trade rules
7. Elephants avoid costly mountaineering
8. How plants avoid feeling the burn
9. Heal thyself: Systems biology model reveals how cells avoid becoming cancerous
10. Female guppies risk their lives to avoid too much male attention
11. Altering genetic blueprint of receptors in brain could help stroke victims avoid brain damage

Post Your Comments:
TAG: Winning neck Giraffes avoid competing with shorter browsers

(Date:9/28/2015)... , Sept. 28, 2015 Synaptics Inc. ... interface solutions, today announced that Lenovo has selected Synaptics ... sensor, FS4202, for its latest smartphone, the Vibe P1. ... access to unlock the device and provide swift access ... The feature-rich Natural ID FS4202 sensor solution utilizes ...
(Date:9/24/2015)... September 24, 2015 ... 2015 Kerv ( http://kerv.com ... lanserar idag världens första kontaktlösa betalningsring på ... 77 000 GBP för massproduktion via crowdfunding.  ... ) , Kerv-bärare kan göra ...
(Date:9/10/2015)... 2015 Report Details The global ... upon previous expectations of revenues, consumer adoption and even ... in which wearables begin to achieve that mass market ... main reasons is the entrance of Apple to the ... market, but the overall size of the wearable technology ...
Breaking Biology News(10 mins):
(Date:10/8/2015)... Oct. 8, 2015 The 2015 Nobel Prize in ... of Texas at Dallas. Aziz Sancar , who earned ... Dallas in 1977, is one of three scientists who ... monitor and repair damaged DNA on a molecular level.  --> ... cell biology from UT Dallas in 1977, ...
(Date:10/8/2015)... , Oct. 8, 2015  The ALS Association, ... ALS Assistive Technology Challenge to revolutionize communication technology solutions ... --> ALS (amyotrophic lateral sclerosis) is ... in the brain and the spinal cord. Eventually, people ... muscle movement, which often leads to total paralysis and ...
(Date:10/8/2015)... Oct. 8, 2015  Today the Wyss Institute for ... of its start-up company Opsonix Inc. The ... Harvard,s Office of Technology Development (OTD) and Opsonix ... therapy for clinical use. --> ... a million people every year in the U.S. — ...
(Date:10/8/2015)... Rapids, MN (PRWEB) , ... October 08, 2015 , ... ... Semiconductor, Medical Device, Aerospace and other technology-driven industries, announces that it is one of ... in Class – Midsize Company.” On Thursday, September 25 Talon Innovations was recognized ...
Breaking Biology Technology:
Cached News: