Birds Versus Bats


 Flying is something that we dream about, that is without standing in line to get on an aircraft, but we’re not built for imitating the birds. The closest we’ve got so far is imitating flying squirrels as demonstrated this week by Gary Connery who hopped out of a helicopter at 2,400 feet (1).

Both birds and bats have been flying about the sky for a very long time and are very proficient. Until now I had just admired their expertise, but Muijres et al haven’t been satisfied with simple admiration (2). They have been checking out their relative aerodynamic efficiencies and have tossed three pied flycatchers, a blackcap, two Pallas’ long-tongued bats and finally two lesser long-nosed bats into a wind tunnel to check the disruption in airflow behind the victims.

The combination of photography and airflow velocity measurements enabled the team to estimate their relative flight efficiencies from such factors as lift-to-drag ratios and mechanical cost-of-transport.

The conclusion for birds versus bats? Well, both species have evolved optimum wings and flight efficiencies for their preferred flight patterns, but on balance they conclude that birds have the edge as flying machines. Hence birds migrate over longer distances and fly faster.

Could be that they have had rather longer in the evolutionary game and maybe bats are generally more laid back, preferring to sleep the winter away rather than having to fly halfway around the world following the sun.


  1. http://news.discovery.com/adventure/connery-plunge-120523.html
  2. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0037335


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The Politics Of Sheep Rules

 Following like sheep is a phrase that is often used as a derogative comment, but perhaps we should give a bit more credit to the sheep because at least one of the sheep knows where it’s going or they’d all be going round in ever diminishing circles like some political party.

Once we start to give a bit more credit to our sheep friends about their directionality, the question arises as to their laterality, this is are they right-hooved or left-hooved? Anderson and Murray worried about this and decided to put it to the test using a T-maze (1). They published their results in the journal Laterality which takes these issues very seriously.

The experiment was done with a total of 309 ewes. They were all white-faced ewes so we don’t know if there is a breed difference and that might be tested in the future. The ewes were tested as they were presented with a fork in the road and had no choice but do what Yogi Berra said – “when you come to a fork in the road, take it.” And they did. Two thirds of the time they turned left.

After making this momentous decision, they had to make a decision on the exit lane to get back to their friends.  On balance, the lefties stayed turning left, while those with an initial right bias tended to switch to the left and return to the fold.

It seems that this might be promising news for the forthcoming elections if the population are really sheep-like as some pundits seem to assume. Those that had their right-fling two years ago may be tending to return to the fold by taking a left direction. We’ll see if the politics of sheep rules in November.
  
  1. http://www.tandfonline.com/doi/abs/10.1080/1357650X.2011.647919



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Eating The Kids


All in the family sounds pretty cozy, but things are not always as simple as it sounds when we are out in the wider world of birds and animals. The old fella, the patriarch, sooner or later will be found lacking and there will be a new sheriff in town.

The bad news then is that often the young offspring will end up as a meal and the new guy will be ready to stamp his genes on the future generations. Infanticide is more common than we like to think when we watch the cuddly babies in the zoo or on our TV screens.

It is not just the new alpha male that indulges in infanticide, but some females do this as well and, unless there is a period of severe deprivation, the logic seems to go against the survival interests of the group, but is it?

Lyon et al worked as a team of biologists, anthropologists and physicists on this problem and published their deliberations in the J. of Theoretical Biology (1,2). Their high level thoughts focused on primates and with idle computers on their hands, they decided to play a three-player game with one female and two males – a new guy and an old guy.

In the game the female can decide to mate with either or both males and there is an underlying assumption that she will be interested in avoiding infanticide as she will have put a fair bit of effort into her young family. After a great deal of electrons rushing about, the result came back that under some conditions a promiscuous female could safeguard her youngsters by mating with both males so that their idea of parenthood was a little blurred.

However, this only works under a limited range of conditions. They found that eating the kids was a common strategy when the times were turbulent with incoming strong guys coming in to take over.  Their conclusion was that infanticide was the probable outcome when the new guy knew that the next generation that he was about to start would clearly be his.

This study was aimed at primates and I guess that the great apes were in the forefront of the thoughts of the authors, but it has echoes throughout world history. I guess that the old saying “it’s a wise child that knows its own father” must stem from times when things were quite and not too turbulent.

  1. http://www.bbc.co.uk/nature/18035811
  2. http://www.sciencedirect.com/science/article/pii/S0022519311000099



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A Friendly Robot Barista


Our morning cup of coffee is not a luxury, but an essential barrier to the rest of the brutal world that is rushing towards us like a cavalry charge when our alarm clock sounds the advance as the sun comes up on a less than ready foot soldier in the battle for the new day.

As we’re never likely, nor should we expect, to have some faithful retainer perspiring over a hot espresso machine before we emerge from our pile of uncoordinated bedclothes to the new world order, wouldn’t it be nice to have a friendly robot barista hard at work?

A prototype is out there in the great city of Seattle, but it is plowing a lone furrow, just waiting to be cloned for the benefit of humanity. Zipwhip, a company that provides a web-texting portal, has manufactured a friendly robot barista that can be urged into activity by punching out a text message from a mobile phone (1,2). Unfortunately, it’s not mine.

Zipwhip say that they are not planning to flood the world with this very desirable robot, but to keep it sequestered away from the light of day in the depths of their Seattle boardroom. They have made the control code open source though, so some engineer can start to do the cloning job.

The prototype makes beautiful coffee whenever it is sent an appropriate text. It’s rumored that it is very even tempered and doesn’t require a smiley face at the end of a text, but will battle phlegmatically on regardless of the sentiment expressed about your espresso.

There is a bonus which is a must have for those living in busy households. It has the ability to write messages (with your name of course) on the foam with a printer loaded with food dye. Perhaps we can get little patriotic flags on appropriate holidays.

  1. http://blog.zipwhip.com/category/geeky-stuff/
  2. http://www.bbc.co.uk/news/technology-18166907


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Flies Flying-By


Flying about in a crowded airspace is difficult enough, but the biggest problem is landing. Not just anywhere mark you, but on a precise spot that is coming up fast and is often moving. Of course, birds do it and bees do it, but so do fruit flies.

Fruit flies aren’t very large and have to rely on their in-built guidance systems to reliably work on the fly.  Van Breugel and Dickinson, in the current edition of the Journal Of Experimental Biology have been scrutinizing the success and failure of fruit fly landing sequences with a combination of high-speed photographs and 3-D tracking software (1).

The touchdown sequence commences with a sharp turn towards the target and a deceleration that the authors explain is governed by the growth of the image size on the fly’s retina. The go/no-go decision is made at the point that the target image takes up an include angle of about 33 degrees of the fly’s vision field.

If the decision is go – the deceleration sequence continues until the target image angle has increased to about 60 degrees and then the landing gear is deployed. On touch down the feet grasp the target. From gear deployment to touchdown was about 50 ms – pretty fast reactions are a must.

If the no-go decision is called for, the fly’s fly-by procedure is a sharp turn away and off to another target. This occurred in 1065 attempts out of 1242-recorded measurements.

Flies flying-by may have been due to too fast an approach or maybe just the fickleness of the fly. They did record some crash landings when flies came in too fast and failed to abort, but none included any fatalities.

  1. http://jeb.biologists.org/content/215/11/1783


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Does Your Cell Phone Disrupt Your Sleep Or Is It Just The Messages?


More and more we are using our cell phones. We may call them “smart,” but they rarely are with the effort we put into our tweets and Facebook updates. Some years ago the idea that they were the cause of cancer was bandied about and studies were done, but no smoking gun was found.

Not that it would have made much difference, as our phones are as addictive as cigarettes. Personally I feel that it’s a pity that manners don’t demand that we go outside to use them in the same manner as we demand of smokers. I find second-hand cell phone listening as irritating as second-hand smoking.

However, a new concern has surfaced and that is does you cell phone disrupt your sleep? This question was in danger perturbing the sleep of Mohler et al so they decided to sort things out with a longitudinal study, which they published last week in the Public Library of Science (1).

After a rigorous exclusion of people with a strong reason to fall asleep such as shift workers or people taking sleeping pills, they settled on a group of 955 participants who had similar exposure to radio frequency electromagnetic radiation and checked their sleep patterns at the start and end of a year. From this group, they picked out 120 individuals for close scrutiny.

The results? Well, they could find no effect of the exposure to radio frequency radiation from cell phones and cell phone towers on the disruption of sleep patterns.


There is always a caveat though. Leaving your cell phone on when you have a large cohort of texters and twitterers might well result in a different experience, but for now we can all rest easy and get a good night’s rest.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0037455

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