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 Modern genetic sequencing tools give clearer picture of how corals are related
17.08.2017 | University of Washington

nachricht The irresistible fragrance of dying vinegar flies
16.08.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

NASA Protects its super heroes from space weather

17.08.2017 | Physics and Astronomy

Spray-on electric rainbows: Making safer electrochromic inks

17.08.2017 | Materials Sciences

Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

17.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>