Behind this incredible method of hunting are the animal kingdom’s most complex eyes, peepers so amazingly evolved that their sophistication seems damn near unnecessary. (That’s me being hyperbolic. They’re anything but unnecessary, of course. Animals don’t just waste energy and resources building worthless features.)

As with bees or flies or crabs, they are compound eyes, but unlike those creatures, mantis shrimp “have a very unusual adaptation in that multiple parts of the same eye view the same point in space,” said biologist Tom Cronin of the University of Maryland, Baltimore County, “which is sort of like having multiple eyes in one, in a way.” Whereas we use two eyes to judge distance, mantis shrimp can do that with a single eye.

Some mantis shrimp species also have the most complex set of color receptors of any animal on Earth, a total of 16 classes compared to our measly four (interestingly, though, half of all stomatopods can’t detect color at all). Their often wild coloration combined with these highly developed powers of color-detection aren’t accidents — they’re likely key in species recognition. You’d hate to try to mate with the wrong species and get a club to the face for your efforts.

On top of that, some mantis shrimp can see a variety of colors in ultraviolet, so “they’re seeing colors that no other animal can see, in a sense,” said Cronin. “Basically color is a property of the nervous system so it’s not really present in the real world, but they can see aspects of the ultraviolet that nothing else can see.”

That’s right: Colors only exist because your brain thinks they do. Your noodle is simply assigning a color to a wavelength of light collected by your retina. Same goes for the mantis shrimp with its ridiculous variety of photoreceptors. (It’s a polychromatic philosophical nightmare, really. What if a mantis shrimp had synesthesia, a human brain disorder in which sounds can produce the experience of color? They’d be freaking out, man, but not really because their brain would perceive it as normal reality. It’s … complicated.)

Anyway, in addition to all of these visual superpowers, the mantis shrimp is the only known critter to see circular polarization of light. Linearly polarized light — the glare off windows and such that’s neutralized by those expensive polarized sunglasses you lost recently — is common, but the circular type is quite rare.

“It’s only created under very special circumstances,” said Cronin, “and the only thing we know about it for sure with the mantis shrimp is that they use it for signaling, so they themselves produce patterns that are circularly polarized on their bodies, which is extremely odd.”

It’d be easy to assume that this staggering amount of information would require an enormous brain to handle, but this is not the case with a mantis shrimp. Whereas our eyes funnel raw data to the brain, in stomatopods the bulk of the processing is done in the eye itself. Indeed, the mantis shrimp’s eye is actually larger than its brain, which if you think about it would look crazy weird if humans were the same way.

“By having all of this complexity at the receptor level,” said Cronin, “you basically are preprocessing everything. So that when it leaves the receptors it’s already streamed into information channels and the brain just basically says, How much is there of this, and How much is there of that, and Make a decision based on that.”

All this data and processing power is pivotal when hunting with such speed and strength, or when defending yourself, for that matter. These things are seriously ornery, like the honey badgers of the sea, and the more information they have to work with to push back against large predators like octopuses, the better.

(Please see website for full article).

We recently covered how you could get client-side information and make it available server side. Do real tests on the client, like measure browser window width and do feature tests. Then save that data to a Cookie. Then next time the page is loaded, you'll have that data in a cookie.

I quite like that technique, and use it, but what if you really want to be using that info on the first page a user sees? You might need to do a page refresh, but you have to be safe about it.

You might be tempted to just test if the cookie is set, and if not, set it and reload. PHP and jQuery here used just for demo purposes, but you can (and I have) done this in any different backend language and with or without a front end library.

<?php if (isset($_COOKIE['_clientInfo'])) { ?>
    
      <script>
        // Do tests, set cookie
    
        location.reload(true); // true means don't use cache
      </script>
    
    <?php } else { ?>
    
      <!-- Proceed normally, using cookie data to make more choices -->
    
    <?php } ?>

This is quite dangerous though. Because:

1. A user might disallow cookies on purpose.
2. A user might be using a browser that doesn't allow cookies.

From what I can tell, iOS app that include a WebView need to specifically turn on the ability to accept cookies, meaning the default is to not allow them.

If either of those above two things are true, you'll get into an infinite-reload situation, which is very bad.

The trick here is to approach it this way:

1. Test if the cookie is present server-side.
2. If the cookie isn't set, set it on the client side with the data you want.
3. Then do another test, client side, if the browser supports cookies or not.
4. If it does support cookies and you haven't used it yet (cookieUsed), then refresh.

Here's a complete document that shows how it could go down:

<!DOCTYPE html>
    <html lang="en">
    
    <head>
      <meta charset='UTF-8'>
      <title>Client Info In Cookie</title>
      <script src="//code.jquery.com/jquery-1.10.2.min.js"></script>
    </head>
    
    <body>
    
        <?php if (isset($_COOKIE['_clientInfo'])) { ?>
    
          <p>Use the data as you see fit!</p>
    
          <?php
              $json = $_COOKIE['_clientInfo'];
              $obj = json_decode(stripslashes($json));
              echo "<p>Browser Width: " . $obj->{'browserWidth'} . "</p>";
              echo "<p>Browser Height: " . $obj->{'browserHeight'} . "</p>";
              echo "<p>Flexbox Support: " . $obj->{'flexboxSupport'} . "</p>";
              echo "<p>SVG Support: " . $obj->{'SVGSupport'} . "</p>";
          ?>
    
          <p>You can use it server-side OR client-side.</p>
    
          <script>
            // You could use the plugin here too, but whatever this is lighter
            var clientInfo = JSON.parse('<?php echo $_COOKIE['_clientInfo']; ?>');
    
            output = "<p>Browser Width: " + clientInfo.browserWidth + "</p>";
    
            $("body").append(output);
          </script>
    
        <?php } else { ?>
    
          <!-- LOAD TESTING LIBRARY, only load when testing -->
          <script src="js/modernizr.js"></script>
    
          <!-- COOKIE LIBRARY -->
          <script src="js/jquery.cookie.js"></script>
    
          <!-- CREATE COOKIE -->
          <script>
    
            var clientInfo = {
              browserWidth: $(window).width(),
              browserHeight: $(window).height(),
              flexboxSupport: Modernizr.flexbox,
              SVGSupport: Modernizr.svg
            };
    
            var cookieVal = JSON.stringify(clientInfo);
    
            // was using document.cookie, this plugin worked better
            $.cookie("_clientInfo", cookieVal, {
              expires: 7
            });
          </script>
    
          <!-- RELOAD PAGE if supported and not used -->
          <script>
            var cookiesEnabled = navigator.cookieEnabled ? true : false;
            if (cookiesEnabled) {
              location.reload(true);
            }
          </script>
    
          <p>Make sure you serve useful content here as well.</p>
    
        <?php } ?>
    
    </body>
    
    </html>

Live demo here.

You may need to mess around with that structure a little to suit your needs. The important part being that you serve useful content no matter what the result is. The worst that can happen then is that you keep trying to set a cookie that will never get set for those users in no-cookie environments. You make the call on how acceptable that is.

You could do more robust testing with something like Detector.

Single Page Refresh for Client Side Data Server Side is a post from CSS-Tricks

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