Stories tagged Life Science

Sep
04
2007

Web work: Two men look over a portion of the huge web a group of spiders have spun in a Texas state park east of Dallas. The white web is turning brown from all the mosquitoes the web has caught.
Web work: Two men look over a portion of the huge web a group of spiders have spun in a Texas state park east of Dallas. The white web is turning brown from all the mosquitoes the web has caught.
I’m a bit late on getting this on the web (pardon the pun), but have you seen what a posse of Texas spiders created last week?

There were numerous reports on this huge web that they spun along about 200 yards of trail in a state park located about 45 miles east of Dallas. Everyone thinks it’s pretty cool except mosquitoes, which get caught up in this tangled web.

"At first, it was so white it looked like fairyland," said Donna Garde, superintendent of the park to the Associated Press. "Now it's filled with so many mosquitoes that it's turned a little brown. There are times you can literally hear the screech of millions of mosquitoes caught in those webs."

Experts say that it’s a classic example of spiders working together as a team to accomplish a huge task. We tend to think of spiders as solitary creatures, but they can work together, as this huge web shows. Exactly how they communicate and organize their activities is still to be determined.

Entomologists from around the country were anxious to get samples of the web to determine what types of spiders created this huge network. Unfortunately, winds and rain are taking a toll on the web and it’s already starting to deteriorate.

So whenever Spider-Man starts getting too high on himself, just tell him to checkout the work of these Texas spiders to bring him back down to Earth.

Aug
25
2007

Break an arm: This arm-wrestling arcade game recently released in Japan is now being recalled after three players have had their arms broken by the artificial arm.
Break an arm: This arm-wrestling arcade game recently released in Japan is now being recalled after three players have had their arms broken by the artificial arm.
Here’s a virtual reality game that got way to real.

The Japanese makers of a new arm-wrestling game are recalling all the machines after three players suffered broken arms at the hands of the mechanized arm of the game.

The game is called “Arm Spirit” and pits players against at mechanical arm. Players work their way up through ten successively harder levels of play, starting out at lower levels simulating a Chihuahua and bar maid and working up to a professional wrestler.

All 150 games that are out on the market in Japanese arcades have been recalled. No machines have been sent to the U.S.

Aug
25
2007

Just out for a jog: Can you run at 18 mph?  (photo by mcdlttx on flickr.com)
Just out for a jog: Can you run at 18 mph? (photo by mcdlttx on flickr.com)
For the younger Science Buzz readers – it’s very important that you understand how cool the Tyrannosaurus Rex is. Super cool. The adults reading this, of course, already know this fact. It’s one of those things you just pick up, and it sticks with you – like riding a bike, or what it feels like to be hungover. You never forget.

However, kids, as you go through your little lives, you will also occasionally encounter those doubting Thomases and sassy Williams who will try to lead you astray, who will try to tell you that the Tyrannosaurus Rex did not, in fact, evolve with the sole purpose of being a reptilian Fonzie. Ignore them! (The major difference between the tyrannosaur species and Arthur Fonzarelli is a simple lack of thumbs. This is barely enough to scientifically distinguish the two.)

These doubters and killjoys will tell you, among other things, that the lizard king was not a running, hunting, killing machine, but more of a flat-tired Cretaceous garbage truck – a scavenger, not a hunter. Part of this argument has to do with dinosaur’s velocity; to be a successful hunter, the T. Rex would have to be able achieve a decent top-speed, if only for a short while. In Jurassic Park, you might remember, the T. Rex was shown galloping along at about 30 mph. The joyless haters have argued that for the tyrannosaurus to reach anything like this speed, the majority of its body mass would have had to have been in its leg muscles, which was almost certainly not the case. The Rex, they say, would more likely have lumbered around looking for already-dead animals to feast off of.

This argument, however, is modeled on the body structure of extant bipedal animals (like flightless birds). Scientists at the University of Manchester have pointed out that the tyrannosaurs weren’t really built like the bipedal animals living today, and have recently developed a new and probably more accurate method of measuring their top speed.

The Manchester researchers developed a computer program that uses the given muscle and bone structure of an animal, and slowly works out the creature’s optimum movement patterns and top speed. They fed data for five dinosaur species (including the T. Rex), as well as that of several existing bipedal animals, into their supercomputer. The scientists had to make an educated guess as to the muscle strength and density of the dinosaurs, but used the same modeling techniques for the dinosaurs as they did for the living animals.

The computer took about a week to work out what each animal’s optimum running gait and posture would be, but finally yielded some interesting results. According to the program, an athletic human’s top speed should be about 18 mph, and an ostrich’s about 35 mph. Both of these are pretty accurate, if just slightly on the slow side (Some Olympic track and field athletes can reach about 29, and ostriches can get to about 40). For the dinosaurs, they found that the famous velociraptor could probably reach about 24 mph, the compsognathus 40 (pretty good for such a little guy), an allosaurus 21, and that the tyrannosaurus rex could do about 18 mph.

18 mph. I think that’s pretty respectable. More than respectable, actually - it’s cool. I mean, I’m fairly cool, and I can’t run 18 mph. And while I’m willing to cede that the tyrannosaurus might have scavenged as the opportunity presented itself, I think 18 mph is more than enough to ambush a hadrosaur or triceratops now and again. At the very least. Also, let’s not be too judgmental over the whole scavenging thing. Who doesn’t, really? I ate half of a potato chip off of my floor this morning. Does that make me a scavenger? No, it makes me an efficient consumer. And it certainly doesn’t mean that I’m not a hunter. Come to my neighborhood and count the rats, and we’ll see who’s a hunter.

Aug
14
2007

In this corner: The champion of heated-tail encounters -- the squirrel. (Photo by Darragh Sherwin at flickr.com)
In this corner: The champion of heated-tail encounters -- the squirrel. (Photo by Darragh Sherwin at flickr.com)
Yesterday was the first time I’ve ever posted anything on this site about rattlesnakes. So what happens but today I came across some more interesting information about rattlers and their encounters with squirrels. And believe it or not, it appears squirrels get the upper hand, or tail, in their confrontations with the snakes.

Californian squirrels have learned how to heat up their tails and shaking them In this corner: The venomous creature that's afraid of a lowly mammal's warmed tail. (Photo courtesy of the U.S. Fish and Wildlife Service)
In this corner: The venomous creature that's afraid of a lowly mammal's warmed tail. (Photo courtesy of the U.S. Fish and Wildlife Service)
aggressively. This action freaks out the rattlers and puts them on the defensive. In a study published this week on Proceeding of the National Academy of Sciences, the report says that the rattlesnakes can sense infrared radiation coming from the squirrels’ tails, a signal that snakes interpret meaning that the squirrels could come and harass them.

Interestingly, adult squirrels are not prey for rattlesnakes. They have a protein in their blood that makes them immune to snake venom. But the snakes do like to go for the baby squirrels. But it appears that the adult squirrels have come up with this “hot-tail” defense to protect their young.

Researchers are still trying to figure out how the squirrels are able to heat their tails. But they’ve discounted it as a natural reaction, because the squirrels only do it when in the presence of rattlesnakes. One theory is that they might be able to shunt the flow of some of their body core blood to go to their tail.

Aug
13
2007

Rattling our cage: A rattlesnake's recently severed head still had enough reflexes left in it or other biological properties to be able to bite the finger of a rancher who had just used a shovel to snap off the head. (Photo courtesy of the U.S. Fish and Wildlife Service)
Rattling our cage: A rattlesnake's recently severed head still had enough reflexes left in it or other biological properties to be able to bite the finger of a rancher who had just used a shovel to snap off the head. (Photo courtesy of the U.S. Fish and Wildlife Service)
Just like Indiana Jones, I’m not too keen on snakes, especially the venomous ones. Now we snake-a-phobes have one more thing to worry about: dead snakes.

Last week a rural Washington state man was bitten by the decapitated head of a rattlesnake. After finding the five-foot snake in the grass while feeding his horses, the man immobilized the snake with a pipe and whacked off its head with a shovel. End of story, right?

Oh no. When he reached down to pick up the snake, the severed head twisted around and bit the guy’s finger. It took about 10 minutes for him to get to the nearby hospital where anti-venom shots were given to him just as his tongue was starting to swell.

I can hear you scoffing: “Urban legend.” But a wildlife biologist in Washington said that it’s possible that the snake’s heat-seeking abilities may still have been intact, or that the snake’s reflexes were still working despite the severing.

Aug
13
2007

Deadly dose: A British teen had severe health problems after consuming 14 shots of espresso in one morning in order to get more energy to do her job. (Flickr photo by augschburger)
Deadly dose: A British teen had severe health problems after consuming 14 shots of espresso in one morning in order to get more energy to do her job. (Flickr photo by augschburger)
Did you hear this one? A teen-ager in England last week had to be rushed to the hospital after suffering an espresso overdose. She slammed 14 shots of the caffine-laced stuff to help her have energy to work the morning shift at her family’s café.

While on duty, her body started to shift into overdrive. She was crying in front of customers and she was acting nervous and jerky. She went home to rest but soon was on her way to the hospital when she became feverish and had trouble breathing. Her heart beats started accelerating, as well.

After she got to the hospital, things started to mellow out. But she was lucky, According to the Mayo Clinic, heavy caffeine consumption -- more than four to seven cups of coffee -- can make you really, really sick. A severe overdose can cause fatal heart palpitations.

Aug
10
2007

A shark, doing it's best: Mostly he just wants to be left alone.    (photo by Mshai on flickr.com)
A shark, doing it's best: Mostly he just wants to be left alone. (photo by Mshai on flickr.com)
Scientists in New South Wales and Florida are testing a new method of measuring the biting force of a great white shark using computer models.

Attempts have been made to measure sharks’ biting force underwater, in captivity and in the wild, although these are known to provide inadequate results. Sharks will generally do weak a “test bite” before applying the full force of their jaws, and these test bites are generally all that’s measured.

In this new experiment, researchers are dissecting a 2.4-meter long great white shark, in part to make an extremely accurate computer model of its anatomy, and in part to drive home the point that the animal should have just allowed them to measure its bite while it was alive. Advanced computing methods, originally developed for “calculating stresses in structures such as bridges,” will then be applied to the model, and should provide a much more accurate range of the shark’s biting force.

This process contrasts sharply with my own, I believe, much more elegant test of shark biting power. There are several simple steps involved in my method: Step 1 – gather a variety of small to medium sized objects. Step 2 - Rate the hardness of these objects, not on an objectively quantified scale, but relatively (for example: The kitten is harder than the pillow, but not as hard as the dictionary). Step 3 - Take these objects to your nearest shark. Get the shark to bite the objects (this can be difficult, but the right combination of chum and verbal abuse should do the trick). You will then have a simple and easy to understand scale of shark biting strength (for example: the shark could crush the pillow, the kitten, the dictionary, and the cookie jar, but not the lawn mower engine). If you still feel, at this point, that you need a measurement that uses more universally accepted units, you can then crush similar objects by yourself, far away from the shark, using free weights, or forty-pound bags of dog food. These can then be easily converted into newtons, or pounds per square inch, or whatever your physics teacher requires.

If the computer model method proves to give reasonably accurate results, I suppose it will then be up to individual researchers to choose that method or mine. It will just depend on whether someone doesn’t want to get their hands dirty, or if they care about style and integrity.

Aug
08
2007

Enjoy the picture
Enjoy the pictureCourtesy Alessio Marrucci
After an “intensive survey of its natural habitat,” the Yangtze River dolphin has been officially declared extinct. So if, as a person, you ever wanted to see one alive, you’re out of luck. And if, as a Yangtze River dolphin, you ever wanted to be alive, also, you’re out of luck.

From a population of thousands in the 1950s, human activity reduced the Yangtze River, or Baiji, dolphin to just a handful of individuals by the turn of the century. Industrialization of the Yangtze River, unsustainable fishing practices, and mass shipping, rather than direct human persecution, placed the Baiji dolphins under extreme pressure, and now they’re all dead, forever. An article in The Guardian states that this is “the fourth time an entire evolutionary line of mammals has vanished from the face of the Earth since the year 1500.” Quite an achievement.

Cross it off your list.

Aug
01
2007

Monarch butterfly: Image courtesy The Divine Miss K.
Monarch butterfly: Image courtesy The Divine Miss K.
As with the earlier post this question comes from the handwritten questions people leave for our featured Scientist on the Spot. Not all the questions fall into the given scientist’s area of expertise, but are still good questions, so I’m taking a stab at answering them.

This question is particularly timely: “How many days does it take for a Monarch butterfly to hatch?” Timely not only because the migration of Monarchs to Mexico begins in August, but also timely for me on a personal level as one of my favorite places to visit with my mom, wife and daughter at the upcoming Minnesota State Fair is the butterfly tent! (Which, devoted fairgoers, has moved to east of the grandstand on the corner of Dan Patch Avenue and Underwood Street.)

I am assuming the question is really how long it takes the butterfly to metamorphize from a caterpillar to a butterfly. I ask because the caterpillars themselves hatch from eggs. The whole process, from egg to butterfly, takes four weeks. The eggs hatch after 7-10 days, and the process of hatching from the chrysalis takes around two weeks. The length of these stages is impacted by the temperature – the cooler it is the longer this process takes.

Monarch migration patterns: Image courtesy Monarch Watch.
Monarch migration patterns: Image courtesy Monarch Watch.
Now, here is one of the really cool things about Monarchs, I think. Each adult butterfly lives about 4-5 weeks. But once a year in the autumn there is a "Methuselah generation" which will live 7-8 months – effectively outliving the combined lifespan of their parents, grandparents, great-grandparents, and great-great-grandparents. It is this generation of butterflies that migrates from Canada and the United States to either Mexico (if they are east of the Rocky Mountains) or to the Southern California cost (if they are west of the Rocky Mountains – though this population seems to be shrinking – see an earlier post on this).

It is incredible to me that these insects can make a migration that they have never made before, that their parents never made, their grand parents never made, as well as their great-grandparents, and great-great-grandparents. Bryan wrote a post on some recent research that butterflies, “sych UV information up with a natural clock in their brain. By combining these two bits of information, monarchs are able to determine the angle of the sun and always head due south,” which I think is really amazing.

Thanks for the great question!

Jul
26
2007

Scent of death?: A Providence, R.I., cat, (not pictured above) that lives at a nursing home has an uncanny ability to find and curl up by residents who are about to die. (Photo by grafwilliam)
Scent of death?: A Providence, R.I., cat, (not pictured above) that lives at a nursing home has an uncanny ability to find and curl up by residents who are about to die. (Photo by grafwilliam)
This has been the main topic of side conversations of floor staff members at the museum today.

Have you heard about this cat in a Providence, R.I., nursing home that has correctly identified the last 25 patients who were to die there?

Oscar, the cat, makes the rounds of the nursing home each morning, just like the medical staff. Some mornings, Oscar will then slip into a room, curl up next to an ailing patient. Within several hours, that patient dies. The cat is so accurate, nursing home staff members will call the family of a resident being visited by Oscar so that they can be present when their loved one passes away.

“He seems to understand when patients are about to die,” says Dr. David Dosa. “Many family members take some solace from it. They appreciate the companionship that the cat provides for their dying loved one.”

Before you get too creeped out by this, doctors at the nursing home say that most of the people Oscar visits are so sick, they’re not aware that he is there. And families, for the most part, seem to be pleased that their loved one got some special attention from Oscar before the death.

Is there science behind this phenomenon? After all, there are dogs that can sniff out oncoming epileptic seizures and there are rats that can sniff out buried land mines.

One theory is that Oscar picks up scents or reads something into the behavior of the nurses who raised him in being able to determine if a patient is going to die. One researcher points out that the only way to know for sure is to do a study of Oscar’s behavior when someone is dying compared to what he does when people aren’t dying.

What do you think is going on here? Share your thoughts with other Science Buzz readers.

Being one never to have a lot of trust in cats, especially after seeing the movie "Cats and Dogs, I’d like that investigation to go a little deeper. Cats can be a lot more devious than appears on the surface.