Featured Research

from universities, journals, and other organizations

When Cobras Spit, There's Not A Dry Eye In The House

Date:
February 17, 2005
Source:
University Of Bonn
Summary:
The red Mozambique spitting cobra stiffens, fixing its gaze on the victim's face, which is moving backwards and forwards in front of it. For several seconds it remains erect like this; then its head flashes forwards. For an instant the fangs in front of its pale pink throat are visible in its wide-open mouth, as they squirt the venom at high pressure towards the victim.

Dr. Guido Westhoff with a spitting cobra.
Credit: Photo : Frank Luerweg/University Of Bonn

The red Mozambique spitting cobra stiffens, fixing its gaze on the victim's face, which is moving backwards and forwards in front of it. For several seconds it remains erect like this; then its head flashes forwards. For an instant the fangs in front of its pale pink throat are visible in its wide-open mouth, as they squirt the venom at high pressure towards the victim. On the plastic visor two red spiral patterns appear. The eyes behind it look surprisingly unperturbed. "I sprayed the visor beforehand with rhodamine," Katja Tzschätzsch calmly explains, "It's a pigment which dyes liquids red. This makes the traces of venom easier to see."

In her undergraduate dissertation the trainee teacher investigated what spitting cobras aim at when spitting. "In the literature it often says: they aim at the eyes," her supervisor Dr. Guido Westhoff, junior lecturer in Professor Horst Bleckmann's team, explains. "However, up to now nobody has investigated it." The cocktail of toxins partly consists of nerve poisons, but also contains components which are harmful to tissue. Through a narrow channel in their fangs the snakes can spray the liquid at high pressure – similar to a bullet in the barrel of a gun. If they manage to hit an eye, the sensitive cornea reacts with severe stinging pain. In the worst case these burns can ultimately lead to blindness.

As guinea pigs Katja Tzschätzsch used four Mozambique and six black-necked spitting cobras from the animal house in Schloss Poppelsdorf. In her experiments she either stood face to face with them herself – protected only by a plastic visor – or she used photos. In addition, for both species she recorded the spitting process using a high-speed video camera. "The snakes really do spit only at moving faces," was her first finding; "movements involving the hand elicited no response from any of the snakes." Only two cobras reacted to the photos. These even spat when Katja touched up the photo, taking out one eye. And even when both eyes were removed, one of the black-necked cobras still remained aggressive. The conclusion: "For really reliable results we would need a larger sample."

Always straight at the eyes

The evaluation of the traces of venom on the photos and the visor revealed how accurate the aim of both species of snake was: the black-necked spitting cobras hit at least one eye eight out of ten times, with the red Mozambique spitting cobras even reaching the target in 100 per cent of cases. However, there was a clear difference in the traces left by the two species: whereas the black-necked cobra sprayed its venom, the attack by the red Mozambique cobra is reminiscent of something shot from a double-barrelled water pistol.

What is decisive for the high degree of accuracy is a pattern of behaviour which researchers were able to observe in both species. "In super slow motion it is clearly visible that the snakes move their heads rapidly when squirting the toxin," Dr. Westhoff explains. "Rather like we do when we wish to use a garden hosepipe to water the flowers of an entire flowerbed." In this way the venom is spread out over a larger area; the chance that it will hit one eye increases.

However, Dr. Westhoff would like to scotch one prejudice: "Cobras only spit when they feel threatened, not to kill their prey," he says; "anything else is a myth." They kill their prey like other poisonous snakes do, by biting them and thereby injecting the venom into their bloodstream, which then proves fatal. Human beings are not on their list of potential prey; even so, these snakes are dangerous – even when they are still very young. Dr. Westhoff reveals, "I was once attacked by a spitting cobra which had just emerged from its shell – it practically spat at me out of its shell."


Story Source:

The above story is based on materials provided by University Of Bonn. Note: Materials may be edited for content and length.


Cite This Page:

University Of Bonn. "When Cobras Spit, There's Not A Dry Eye In The House." ScienceDaily. ScienceDaily, 17 February 2005. <www.sciencedaily.com/releases/2005/02/050212194818.htm>.
University Of Bonn. (2005, February 17). When Cobras Spit, There's Not A Dry Eye In The House. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2005/02/050212194818.htm
University Of Bonn. "When Cobras Spit, There's Not A Dry Eye In The House." ScienceDaily. www.sciencedaily.com/releases/2005/02/050212194818.htm (accessed July 24, 2014).

Share This




More Plants & Animals News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) — An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) — The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) — A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. Video provided by Newsy
Powered by NewsLook.com
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) — ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:  

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile iPhone Android Web
          Follow Facebook Twitter Google+
          Subscribe RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins