Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Explaining Tsavo’s Maneless Man-Eaters

12.04.2002


The phrase "king of the jungle" invariably conjures up the image of a majestic, tawny cat with a fluffy mane framing its face. But in fact not all male lions have big hair. In Kenya’s Tsavo National Park--famed for the man-eating lions that reportedly terrorized railroad workers there in the late 1800s--a number of males lack manes altogether. Exactly why this should be the case--or why any lions should have manes, for that matter--has been difficult to explain. To that end, the results of a new study, published online today by the Canadian Journal of Zoology, could prove insightful.


Image: John Weinstein/Courtesy of the Field Museum



Over the years, researchers have put forth several social hypotheses aimed at explaining the main function of the mane in these group-living felines, ranging from intimidation (a big mane makes an animal look bigger) to physical protection for the head and neck areas from other lions to sex appeal. At the same time, however, manes are expensive: they offer unnecessary and perhaps harmful insulation to beasts in hot areas, they make the animals more conspicuous to both prey and competitors, and all that extra hair provides more stuff for thorns and brambles to latch onto.

To shed some light on the matter, Roland Kays of the New York State Museum in Albany and Bruce Patterson of the Field Museum in Chicago set out to test one of the social hypotheses: that mane size should vary as a function of female group size. According to this model, increased female group size should ratchet up the sexual selection pressure for long, flowing manes on males. Males with reduced or nonexistant manes, in contrast, should predominate in areas characterized by smaller female groups.


Observations of the Tsavo lions did not bear these predictions out. The researchers found that average female group size was large for the species. Yet most males were maneless or retained only remnant tufts on their head or neck. The more likely explanation for Tsavo’s maneless males, Kays and Patterson conclude, is that the blisteringly hot, arid, thornbrush-covered Tsavo habitat makes mane maintenance too costly.

The researchers further note that in contrast to savannah-dwelling populations, the prides observed in Tsavo consisted of a lone male defending a group of females. "How single, maneless males are able to hold relatively large groups of females remains unknown," they write. But it may be that these males have higher testosterone levels, which could account for both their "baldness" and their ability to single-handedly fend off groups of challengers.

Kate Wong | Scientific American

More articles from Life Sciences:

nachricht More genes are active in high-performance maize
19.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht How plants see light
19.01.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>