Lemur with a baby on its back.

Madagascar: Politics

Western powers and Madagascar's African neighbours have accused President Rajoelina of trampling on democracy, and some in the military have grown disenchanted with him in recent months.
Most Malagasy, as the nation's people are known, live in poverty, which ecotourism, vanilla production and the recent discovery of oil have done little to alleviate. The country is famed for its lemurs and other unique wildlife ...

Live Longer, Walk Faster : Dean's Corner

Live Longer, Walk Faster : Dean's Corne
(Studenski, S. et al. JAMA 2011;305:50-58).
Staying active, along with a balanced health diet, is probably the best way to age gracefully. An elegantly simple study was just published in the Journal of the American Medical Association that clearly demonstrates the relationship between longevity and walking speed. Researchers studied close to 35,000 people aged 65 years or above (a mean of 74 years) with data taken from six to 21 years.

I love studies such as this - ask a simple question, propose a clear experimental design, and analyze the data carefully, including a statistical analysis. They did not prove that if you walk faster, you can live longer. Instead, they demonstrate that walking speed can be an accurate predictor of longevity, useful for informing physicians about how best to treat their patients. For example, if a patient is predicted to live well more than a decade, it makes sense to consider long term preventative strategies.

According to the paper:

How might gait speed be used clinically? First, gait speed might help identify older adults with a high probability of living for 5 or 10 more years, who may be appropriate targets for preventive interventions that require years for benefit. Second, gait speed might be used to identify older adults with increased risk of early mortality, perhaps those with gait speeds slower than 0.6 m/s. In these patients, further examination is targeted at potentially modifiable risks to health and survival. A recommended evaluation and management of slow walking includes cardiopulmonary, neurological and musculoskeletal systems.6​,18 Third, gait speed might promote communication. Primary clinicians might characterize an older adult as likely to be in poor health and function because the gait speed is 0.5 m/s. In research manuscripts, baseline gait speed might help to characterize the overall health of older research participants. Fourth, gait speed might be monitored over time, with a decline indicating a new health problem that requires evaluation. Fifth, gait speed might be used to stratify risks from surgery or chemotherapy. Finally, medical and behavioral interventions might be assessed for their effect on gait speed in clinical trials. Such true experiments could then evaluate causal pathways to determine whether interventions that improve gait speed lead to improvements in function, health, and longevity.

The data provided herein are intended to aid clinicians, investigators, and health system planners who seek simple indicators of health and survival in older adults. Gait speed has potential to be implemented in practice, using a stop watch and a 4-m course. From a standing start, individuals are instructed to walk at their usual pace, as if they were walking down the street, and given no further encouragement or instructions. The data in this article can be used to help interpret the results. Gait speed may be a simple and accessible indicator of the health of the older person.

This gives us something to think about the next time you decide to take a walk - are you a "shuffler" or do you have to slow yourself down sometimes?

Lemur Week: Ringtailed Lemurs Look Where You're Looking : The Thoughtful Animal

Lemur Week: Ringtailed Lemurs Look Where You're Looking : The Thoughtful Animal

Madagascar: British photographer Nick Garbutt's 20-year survey of the island's wildlife - Telegraph

Madagascar: British photographer Nick Garbutt's 20-year survey of the island's wildlife - Telegraph: 

"adult male fossa (Crytoprocta ferox) prowls on the deciduous forest floor of the Kirindy Forest,"

Madagascar Lemurs

http://www.afrol.com/features/35163


As the evolution of species through natural selection had been scientifically accepted, Darwin's theories seemed to fit perfectly to the large island of Madagascar. The island's isolated fauna seemed to have frozen a moment of evolution when it drifted away from Africa, back to the time when lemurs had yet to evolve into monkeys and apes. Even modern encyclopaedias refer to this age-old theory, stating that "the resulting isolation left Madagascar's plants and animals to evolve independently" (encyclopedia.com).

Indeed, Madagascar has more unique species of animals than any location except Australia, which is 13 times larger. The island's population includes 70 kinds of lemurs found nowhere else and about 90 percent of the other mammals, amphibians and reptiles are unique to its 587,000 square kilometres.

The original theories about the origin of Madagascar's unique fauna stem from an age when the processes of plate tectonics were not well known. Critically, scientists of those times were unable to date geological processes.

Dating processes of fossils and sediments however improved. As it became more and more probable that Madagascar drifted away from Mozambique before the lemurs had evolved in Africa, the theory had to be altered. Scientists now held that the animals arrived on Madagascar via a land bridge that was later obliterated by shifting continents.

Yet, the land bridge hypothesis also is problematic in that there is no geologic evidence that such a bridge existed during the time in question. Also, there are no large mammals such as apes, giraffes, lions or elephants, indigenous to Madagascar. Only small species such as lemurs - the island's signature species - hedgehog-like tenrecs, rodents, mongoose-like carnivores and similar animals populate the island.

But already a century ago, some scientists started doubting the prevailing split-and-isolation theory. In 1915, the first alternative theory was launched, saying many of the animals found in Madagascar could have rafted to the island.

Rafting would have involved animals being washed out to sea during storms, either on trees or large vegetation mats, and floating to the mini-continent, perhaps while in a state of seasonal torpor or hibernation.

As improved dating made the land bridge theory even less plausible, the very influential palaeontologist and evolution theorist George Gaylord Simpson in 1940 launched a more detailed rafting theory. Mr Simpson introduced the concept of a "sweepstakes" process to explain the chance of raft colonisation events taking place through vast stretches of geological time. Once the migrants arrived on the island, their descendants evolved into the distinctive and sometimes bizarre forms seen today.

Though influential, Mr Simpson failed to convince all scientists - and laymen at large. His theory had a major flaw. The prevailing currents and winds in Mozambique Channel - the straight splitting Madagascar from the continent - flow and blow south and southwest, away from, not toward, the island.

Since this controversy, no generally accepted theory could explain how the lemurs, flying foxes and narrow-striped mongooses got to the large, isolated island of Madagascar sometime after 65 million years ago. The split-and-isolation theory 

Different species of endemic mouse lemurs (Microcebus) occurring in the western half of Madagascar. Microcebus are the world's smallest living primates and some species are limited to small geographic areas.

© Peggy Macnamara/The Field Museum

has therefore prevailed in popular science and belief, despite a 60 million year timing error.

Professor Jason Ali of the University Hong Kong, who has a research focus in plate tectonics - the large-scale motions of the Earth's outer shell - a few years ago caught interest in this unsolved major evolutionary mystery.

Mr Ali kept running across the land bridge hypothesis in the course of his work. The question intrigued him because the notion of a bridge between Madagascar and Africa appeared to break rules of plate tectonic theory. A background in oceanography also made him think ocean currents between Africa and Madagascar might have changed over time.

"Critically, Madagascar and Africa have together drifted more than 1,600 kilometres northwards and could thus have disrupted a major surface water current running across the tropical Indian Ocean, and hence modified flow around eastern Africa and Madagascar," says Mr Ali, an earth sciences professor. Maybe, he thought, Mr Simpson's rafting theory from 1940 still could prove right.

That led the Hong Kong professor to contact Professor Matthew Huber, a palaeoclimatologist who reconstructs and models the climate millions of years in the past, at the US Purdue University. Mr Huber has a particular interest and expertise in ocean currents and had recently developed a very potent programme modelling ancient ocean currents and climates.

The Purdue professor was able to show that 20 million to 60 million years ago, when scientists have determined ancestors of present-day animals likely arrived on Madagascar, currents flowed east, toward the island. Climate modelling showed that currents were strong enough - like a liquid jet stream in peak periods - to get the animals to the island without dying of thirst. The trip appears to have been well within the realm of possibility for small animals whose naturally low metabolic rates may have been even lower if they were in torpor or hibernating.

Mr Huber's computer modelling also indicates that the area was a hotspot at the time, just as it is today, for powerful tropical cyclones capable of regularly washing trees and tree islands into the ocean.

"It seems likely that rafting was a distinct possibility," their study concludes. "All signs point to the Simpson sweepstakes model as being correct: Ocean currents could have transported rafts of animals to Madagascar from Africa during the Eocene."

The new theory, published in the renowned journal 'Science' on 4 February 2010, has already found some support. "The raft hypothesis has always been the most plausible," says Anne Yoder, director of the Duke University Lemur Center. She specialises in the evolutionary history of Madagascar. "But Ali and Huber's study now puts hard data behind it," she adds.

The theory would also solve a problem related to new knowledge about Madagascar's evolutionary history. The island's animals appear to have arrived in occasional bursts of immigration by species rather than in a continuous, mixed migration. They likewise appear to have evolved from single ancestors, and their closest relatives are in Africa, scientists say. All of which suggests Mr Simpson's old theory was correct.

While the first reception in the scientific community seems to be positive, it remains to be seen whether the currently applied computer models of the region's palaeoclimate and ancient currents will have to be corrected. But surely, the popular split-and-isolation theory prevailing in most textbooks, in encyclopaedias and in popular belief, will not disappear for years to come.

Also surely, Madagascar's fascinating and poorly studied biodiversity will continue to pose challenges and present surprises for researchers and laymen in the future.

Only in 2006, three new species of lemurs were identified on the Great Island. Globally, new mammals are very nowadays very seldom identified, again showing how poorly Madagascar's amazing ecology has been studied.

Also in 2006, the first-ever comprehensive theory explaining the island's exceptionally rich biodiversity was presented. This is the only thorough study into Madagascar's evolutionary history and regional speciation. Also the island's geology and palaeoclimate is understudied.

Major discoveries are still to be expected on the Great Island. 

By afrol News staff and Greg Kline

© afrol News

The Tale of Larry the Lemur

Here is a story you won't believe.
Larry the Lemur, Randy the Rat, and Carl the King Snake...

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   The Adventures of Larry the Lemur

   Ralph Castaneda / iUniverse

   Children's Middle Readers 

   Larry the Lemur is overlooked by his family and his parents--and that's just the way he likes it! Larry enjoys taking advantage of his vivid imagination and his parents' forgetfulness to raise havoc in the forest!