Featured Research

from universities, journals, and other organizations

The big sleep: How do you anesthetize a hippopotamus?

Date:
July 3, 2012
Source:
Veterinärmedizinische Universität Wien
Summary:
It may rank fairly low in most lists of pressing problems to be solved but an increasing number of zoos and wildlife collections as well as gamekeepers nevertheless need to come up with an answer:  How do you anaesthetize a hippopotamus? Difficulties are posed not only by the undesirability of approaching waking animals but also by hippos’ unique skin morphology and by the animals’ sensitivity to standard anesthetic methods. A new procedure has now been described.

How do you anesthetize a hippopotamus?
Credit: © UryadnikovS / Fotolia

It may rank fairly low in most lists of pressing problems to be solved but an increasing number of zoos and wildlife collections as well as gamekeepers nevertheless need to come up with an answer: How do you anesthetize a hippopotamus? Difficulties are posed not only by the undesirability of approaching waking animals but also by hippos' unique skin morphology and by the animals' sensitivity to standard anesthetic methods.

A new procedure is now described by the group of Chris Walzer at the Research Institute of Wildlife Ecology of the University of Veterinary Medicine, Vienna and published in the current issue of the Journal of the American Veterinary Medical Association.

All zoo animals -- and sometimes also wild animals -- occasionally need veterinary treatment and anesthesia is clearly required in many cases. For most animals the procedures are well established but for a variety of reasons it has proven difficulty to anaesthetize hippopotamuses. The thick skin and the dense subcutaneous tissue make it difficult to introduce sufficient amounts of anesthetics and opioid-based anesthetics often cause breathing irregularities and occasionally even death. In addition, the level of anesthesia is only rarely sufficient to enable surgery to be undertaken: few vets wish to be around when a drugged hippopotamus starts to wake up.

Together with Thierry Petit from the Zoo de la Palmyre, France, and collaborators in Germany and Israel, Gabrielle Stalder and Chris Walzer from the Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna (Vetmeduni Vienna) have now developed a new anesthetic protocol based on the use of two non-opiate drugs, medetomidine and ketamine. The procedure has been tested on a total of ten captive hippopotamuses, all of which were successfully anesthetized to an extent that enabled surgery -- although due to the difficulty to estimate their exact weight some animals needed additional doses of anesthetic before they could be safely handled. Crucially, all animals recovered rapidly and completely from the procedure and showed no lasting after-effects.

Diving during anesthesia? This does not mean that the anesthesia always passed without incident: five of the ten animals stopped breathing for periods of up to nearly ten minutes. But in each case the hippopotamus spontaneously recommenced breathing without the need for any intervention. The VetMed scientists interpret the temporary suspension of breathing as a dive response: their aquatic lifestyle means that hippopotamuses are able to hold their breath for relatively long periods, so it is likely that the animals also "dived" during the period of unconsciousness.

The researchers thus had a unique opportunity to learn what happens when hippopotamuses stop breathing. The level of oxygen in the blood naturally decreases but this is not associated with an increase in heart rate nor, surprisingly, with increased levels of lactate. As Walzer says, "all diving mammals have evolved a strategy to cope with the shortage of oxygen while they are underwater. The reaction of hippopotamuses to anesthesia suggests that they do not switch to anaerobic metabolism when they dive but possibly have other mechanisms to help them use the oxygen in their blood more efficiently. The hooded seal is known to have very high levels of myoglobin in its muscles: maybe the hippopotamus has a similar trick to help it survive?"


Story Source:

The above story is based on materials provided by Veterinärmedizinische Universität Wien. Note: Materials may be edited for content and length.


Journal Reference:

  1. Gabrielle L. Stalder, Thierry Petit, Igal Horowitz, Robert Hermes, Joseph Saragusty, Felix Knauer, Chris Walzer. Use of a medetomidine-ketamine combination for anesthesia in captive common hippopotami (Hippopotamus amphibius). Journal of the American Veterinary Medical Association, 2012; 241 (1): 110 DOI: 10.2460/javma.241.1.110

Cite This Page:

Veterinärmedizinische Universität Wien. "The big sleep: How do you anesthetize a hippopotamus?." ScienceDaily. ScienceDaily, 3 July 2012. <www.sciencedaily.com/releases/2012/07/120703120622.htm>.
Veterinärmedizinische Universität Wien. (2012, July 3). The big sleep: How do you anesthetize a hippopotamus?. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2012/07/120703120622.htm
Veterinärmedizinische Universität Wien. "The big sleep: How do you anesthetize a hippopotamus?." ScienceDaily. www.sciencedaily.com/releases/2012/07/120703120622.htm (accessed August 1, 2014).

Share This




More Plants & Animals News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Vaccine Might Be Coming, But Where's It Been?

Ebola Vaccine Might Be Coming, But Where's It Been?

Newsy (Aug. 1, 2014) — Health officials are working to fast-track a vaccine — the West-African Ebola outbreak has killed more than 700. But why didn't we already have one? Video provided by Newsy
Powered by NewsLook.com
Study Links Certain Birth Control Pills To Breast Cancer

Study Links Certain Birth Control Pills To Breast Cancer

Newsy (Aug. 1, 2014) — Previous studies have made the link between birth control and breast cancer, but the latest makes the link to high-estrogen oral contraceptives. Video provided by Newsy
Powered by NewsLook.com
Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) — Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) — With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
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