Stories tagged rodents

It's Friday, and y'all know what that means. Yup, time for a new Science Friday video.

Science Friday
Science FridayCourtesy Science Friday

This week,

"Many mammals have whiskers but not all whisk. Cats don't. Rats do. To whisk, rats use special muscles in their face to brush their whiskers against an object. From the bending bristles, rats seem to be able to decode an object's shape and texture and Mitra Hartmann, engineer at Northwestern University, wants to understand how. This week, Hartmann and colleagues published a 3D whisker model, which she says will help quantify what information the brain receives from a whisk."

Feb
14
2010

Naked Mole Rat: a mighty survivor both hairless and nearly blind
Naked Mole Rat: a mighty survivor both hairless and nearly blindCourtesy MissTessmacher
The naked mole rat (Heterocephalus glaber) is truly one of the most remarkable animals on this earth. On average 3 inches long and weighing just over an ounce, one would not think this creature so high and mighty. However, its unusual traits have brought it under more medical scrutiny and established an ever increasing presence in research laboratories. Stories have rung for years about how the only species to survive a world Armageddon would be cockroaches and rats. My money is on the naked mole rat.

While called a rat, they are one of 37 species of mole rats globally and are more closely related to guinea pigs and porcupines than other Rodentia. Limited to parts of East Africa, they spend their lives under ground in a highly social commune of individuals, all governed by a queen. This is very similar to the eusociality seen in bees and ants. The queen is the only female to breed, with all other individuals serving as guards or workers. This unusual social life for a mammal in a colony can lead to fierce competitions among females when the old queen dies. It may take days or weeks of power struggle before life in the colony returns to normal.

In search of plant tubers for sustenance, they dig through the dirt with their teeth, developing a system of burrows that can carry on for miles. One of the naked mole rats remarkable features is its ability to survive in the high carbon dioxide environments of these tunnels. Their extremely low metabolic rate and high absorption of oxygen allow them to overcome the limitations of the cramped and congested space. Research has found that these mole rats are void of a pain transmitter called Substance P found in other mammals, and have an uncanny resistance to the oxidative stress of daily metabolism.

Researchers hope this could lead to new insights into the process of aging. Captive research colonies have had individuals live as long as 28 years. That is more than nine times as long as a research mouse! This longevity and unique durability lead even more scientists to consider the naked mole rat for captive study populations in the fight against other afflictions like stroke and cancer. If these superman-like traits haven’t given you a deeper appreciation for such a tiny hairless creature, perhaps you just need a clever ditty to sing their praises. Oh! …you so UGLY!

Jan
21
2008

Like this, maybe: but way bigger.
Like this, maybe: but way bigger.Courtesy nao-cha
A 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.

Apr
21
2006

The newest fighting force on the war on terror: white lab rats.

A team of six little rodents are now part of the arsenal of tools that Columbian police are using to sniff out bombs and land mines. And it’s their little size that’s the biggest thing going for them.

Police are preparing to use the rats to find and defuse the more than 100,000 land mines that pepper the Columbian countryside, the result of hostilities between the Columbian government and leftist rebels.

The rats, which weigh less than half a pound, don’t trigger any explosions when they walk atop the mines. Dogs or people, who’ve tracked down mines in the past, don’t have that light-weight luxury.

Over the past year, the rats have gone through daily training where they are placed in a maze which holds C-4 explosives and other bomb making materials. When they find a target, they’re rewarded: a cracker for their palates and a stroke on the top of their heads.

So far, the rats have been able to locate explosives 83 percent of the time. But they won’t get to try their skills out in the field until they hit the 100-percent mark, a benchmark trainers figure they’ll get to in another six months.

It’s believed Columbia is the first country to use rats for finding mines and bombs, but larger rodents have been used for similar work in the Sudan.

If the experiment works out, the little critters could have a big impact. Columbia has the highest number of land mine victims in the world. Last year, 1,070 people were involved in mines explosions. About one quarter of those people died.

And in a related development, researchers in New York are developing “Roborat.” The technology allows police to control rats’ movements by sending electronic impulses to their brains via miniature electronic backpacks strapped to their bodies.