UPDATE: Supernavigators Chapters 1-6

Supernavigators: Exploring the Wonders of How Animals Find Their Way - David Barrie


TITLE:  Supernavigators:  The Astounding New Science of How Animals Find Their Way


AUTHOR:  David Barrie




Regardless of whatever my opinion will be of this book by the time I finish it, at the moment I LOVE this author (and maybe the publisher) to bits.  David Barrie actually references his book properly.  Each creature or "story" described so far in the book as a superscripted numeral that refers to the actual journal article or other reference used by Barrie!  None of this BS where you wonder where that particular bit of information comes from or searching for the reference at the back of the book and wondering if it's the relevant one, or odd-ball and irritating referencing techniques/formatting.


NOTE 2: 

The chapters are generally fairly short, with no fashion commentary, but a few paragraphs (so far) dedicated to personal anecdotes and biographical details of various scientists.  I would have liked a bit more information of the actual biology involved in the navigational "organs" but maybe this comes later on?  The text is easy to read/follow but not simplistic or "chirpy".  This may be a popular science book but there is more emphasis on the hows and whys of various discoveries than on being overly popular.



Chapter 1 starts off with the ability of "simple" organisms (e.g. bacteria, slime moulds, jelly-fish, plankton etc) to determine where they are and where they are going.


"The so-called magnetotactic bacteria contain tiny magnetic particles that, when joined end-to-end, act like microscopic compass needles. These “needles” force the bacteria to align themselves with the earth’s magnetic field and thereby help them find their way down to the oxygen-poor layers of water and sediment where they flourish. The needles found in bacteria from the northern hemisphere have the opposite polarity to those in the southern hemisphere. A simple example of the power of natural selection."

"Even more impressive are the brainless assemblies of single cells known, rather unappealingly, as slime molds. These simple organisms can slowly but surely ooze their way toward a supply of glucose hidden at the bottom of a U-shaped trap. To do so, they employ a simple kind of memory that enables them to avoid revisiting places they have already explored.  They are also adept at solving a problem that human designers find challenging: the construction of an efficient rail network.


Researchers found that one particular slime mold, when presented with lots of oat flakes arranged in a pattern mimicking the layout of cities around Tokyo, set about building a network of “tunnels” to distribute the nutrients they extracted from the flakes. Amazingly enough, the network eventually came to match the actual rail system around Tokyo. The slime mold achieves this feat first by creating tunnels that go in all directions, and then gradually pruning them, so that eventually only those carrying the largest volume of nutrients (read “passengers”) are left."

 I love slime moulds!


Chapter 2 deals with finding your way using visual landmarks.  Examples include the Inuit and Aboriginal Australians, and how their navigational demands have an effect on their language.  This chapter also focuses on studies done involving ants and their navigational technique, which seems to involve sight rather than smell.


Chapter 3 also deals with animals using landmarks but of a more unusual variety.  Here Barrie explores the extraordinary sensitivity of the sweat bee’s compound eyes, brain functioning, and visual cues that allows it to navigate, by sight, through a rain forest canopy in nearly total darkness.  Barrie also explores the navigational abilities of fish - the lateral line organs, blind cave fish, fish that use visual landmarks, the different navigational abilities of pond and river fish, electric landmarks used by sharks and eels (and bumble bees) - and the ability of birds to find their way to stored food and to find their way home (homing/messanger pigeons) via visual landmarks.


 "There is a legend that the Rothschild bank made a killing in 1815 because they received news by pigeon post of the outcome of the battle of Waterloo ahead of the markets. It is a good story, though apparently without foundation. The Rothschilds did, however, develop a system of communication using pigeons and it was up and running by the 1840s, some years before the first electronic telegraph systems were operational."





Chapter 4 starts of with a crash course in navigating by the sun.  I'm liking this author more and more.  He actually included a sketch to illustrate a point. Chapter 4 and Chapter 5 focus on the way some species use the sun for navigation, in combination with the organisms internal clock, e.g. ants and bees. 




Chapter 6 involves long trips over the oceans by humans and migrating species. There is an interesting section of ocean navigation before the invention of modern equipment and reliable methods to determine longitude [Barrie wrote another book on this subect] involving not so accurate magentic compasses, stick-on-a-string aka chip log (where the term knots comes from) and the lead line aka glorified plumb line (to find out how deep your ocean spot was and if you stuck some fat on the end, you could determine what type of submarine ground you were floating over - provided the rope was long enough to reach the bottom).  "Dead reckoning" sounds like a rather hazardous method of ship navigation.  I'm surprised anyone got where they were supposed to be going.  This chapter also includes inertial navigation and the odd habit of humans to walk around in circles when lost.