Stories tagged south america

Like this, maybe: but way bigger.
Courtesy nao-chaA boulder in Uruguay has recently yielded the remains of a 2000-pound extinct rat. Well, maybe not a rat, exactly, but “capybara” doesn’t summon quite so effective of an image, and “giant beaver” has its own issues. The fossils, at any rate, come from what has now been declared the largest rodent ever to roam the earth: 2000 pounds, and about nine feet from its buckteeth to the tip of its stubby tail – bigger than a bull.

The largest rodent living today is, of course, the 140-pound capybara, a semi-aquatic, South American monstrosity. The previous record holder for “largest rodent” was also from South America, and weighed in at a measly 1500 pounds. 1500 pounds is bigger than me, but hardly anything special next to its one-ton cousin. I expect the fossils of the old record holder will be thrown out, or ground up and put on someone’s driveway.

The gargantuan rat-thing would have lived alongside giant ground sloth, Volkswagen Bug-sized armadillos (glyptodonts), and massive “Terror Crane” birds (the SMM has examples of all three in the Dinosaurs and Fossils gallery, if you’re interested). It is most likely that the creature was a vegetarian, and it may have used its huge teeth in much the same way as a modern beavers do. Alternatively, says one researcher, the teeth may have been used for fighting – little is known about the giant rodents still, and, while large size often works as its own defense, the creature would have also shared its habitat with predators like saber-toothed cats. When in doubt, I always say, pick the most action packed explanation.

Paleontologists are still not sure how the other species tolerated living with such a large rat, but are optimistic that further research will satisfactorily illuminate the situation.

Tags : rodents, paleontology, south america, huge

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Aedes aegypti mosquito
Courtesy Photo courtesy Centers for Disease Control and PreventionA re-emerging threat
Dengue fever is making a come back in South America and some fear it could become a problem again in the US as well. The year 2007 was an epidemic record-breaking year there was an 11% increase in reported dengue cases when comparing 2006 to 2007. Some even fear it could be spreading to the US. There was a recent article in the Los Angeles Times about it reappearing in the US.
What is dengue fever?
Dengue is a viral infection spread by the predominantly urban species Aedes aegypti mosquitoes. In recent years dengue has become a major international public health concern. Dengue is found in tropical and sub-tropical regions around the world, predominantly in urban and semi-urban areas.
Dengue fever is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death. Dengue haemorrhagic fever is a potentially deadly complication that is characterized by high fever, haemorrhagic phenomena--often with enlargement of the liver--and in severe cases, circulatory failure.
Why is dengue making a come back?
Potential reasons include climate influences like global warming, El Niño / Southern Oscillation and La Niña, both of which influence the intensity and duration of the rainy seasons and hurricanes or induce intense droughts and damage to biodiversity. Another potential cause is population growth and increased opportunities for mosquitoes to breed.
On the other hand, micro factors exist that are dependent on the agent (virus) and the vector (mosquito)—which at times exhibits a growing resistance to insecticides—and the host, all of which closely influence the manifestation of the disease and its more serious forms.

Tags : disease, virus, mosquito, vector borne, health, infectious disease, south america, dengue fever, fever

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