May 6th, 2008

JC - Screentone

artificial beak for wounded bald eagle

Beauty, a rescued bald eagle, is going to get an artificial beak to replace the part of her beak that was shot off.

The 15-pound eagle was found in 2005 scrounging for food and slowly starving to death at a landfill in Alaska. Most of her curved upper beak had been shot away, leaving her tongue and sinuses exposed. She could not clutch or tear at food.

Beauty was taken to a bird recovery center in Anchorage, where she was hand-fed for two years while her caretakers waited in vain for a new beak to grow.

aye aye captain

More on Mantis Shrimp

prompted to actually sit down and write this by rosequoll's post (hello!) about Mantis Shrimp arms...

Mantis Shrimp Eyes! And some other bits.

In addition to their amazing arms, the Stomatopods crustaceans enjoy a number of other unique and amazing features. Nannosquilla decemspinosa, for example, will curl into a circle and roll away after retreating water if left behind by the tide. And the planktonic larva of some species are golf-ball sized spheres with 4 razor-sharp spikes sticking out.

But it's their eyes - their amazing, unmatchable eyes - that continue to stun researchers.

Not only is each eye perched on a movable stalk, but the facets on each are so arranged that the thumbsplitter can watch you from three different directions from each eye. This gives them incredibly good triangulation on their prey, or your finger.

Further, the eye is filled with an incredible assortment of pigments. Human eyes can detect a mere 3 colours, and combine the results to give us what we laughably call full-colour vision.

The midband of each eye consists of six parallel strips - the first four have eight different types of light-sensitive cell, with pigments that respond to different wavelengths of light. With these, the prawn-killer's vision extends from the ultraviolet to the infra-red. And they've got tunable filters to match light conditions.

Rows 5 & 6 have photoreceptors for polarised light - that is, light vibrating in just one direction - like a piece of string tied to a hook and wriggled up and down. We already knew about their ability to detect linear polarisation - indeed, lots of animals use it - bees for example use the polarisation pattern of the sky to determine bearings even on partly clouded days. But mantis shrimp go one step further - and are the only animals that can detect circularly polarised light - light that twists in a helix, one way or the other.

This gives them even more advantages over other predators, and animals that would try to eat them. Also, by signaling to each other with circularly polarized pigment patterns on their bodies, they have a communication channel that their predators won't be able to detect - a private channel for them to use for such messages as "Hey baby, come check out my pleopods". You'll be pleased to know, Rose, that your Peacock Shrimp is even more sensitive to this secret channel than most species of stomatopod. But I hope that you weren't planning on keeping anything else in the same tank, because they're not very community-minded beasts.

Details and more info here, at Not Exactly Rocket Science

(Peacock) Mantis Shrimp

Posting this guy, because (and because I didn't see any in the tags)! I got one today. Eeeeeee. He's just a little guy, and he just shed so he's hiding in the back of the tank whining to himself. He's only about 3 cm long, so just a baby. They can reach lengths of up to 30cm (12 inches). I think...I will need a bigger tank in a year. =) And probably an acrylic one as well.

After watching the awesome video on the pistol shrimp (of which I have two, an orange one and a clear/green one; I'm having a lot of trouble finding the exact species names for each) I figured this guy is just as cool, if not cooler because they get so much bigger and can actually shatter the glass of an aquarium.

Articles and videos:

"Both types strike by rapidly unfolding and swinging their raptorial claws at the prey, and are capable of inflicting serious damage on victims significantly greater in size than themselves. In smashers, these two weapons are employed with blinding quickness, with an acceleration of 10,400 g and speeds of 23 m/s from a standing start  [5], about the speed and force of a .22 caliber bullet. Because they strike so rapidly, they generate cavitation bubbles between the appendage and the striking surface  [5]. The collapse of these cavitation bubbles produce measurable forces on their prey in addition to the instantaneous forces of 1,500 N that are caused by the impact of the appendage against the striking surface, which means that the prey is hit twice by a single strike; first by the claw and then by the collapsing cavitation bubbles that immediately follow  [6]. Even if the initial strike misses the prey, the resulting shock wave can be enough to kill or stun the prey.

The snap can also produce sonoluminescence from the collapsing bubble. This will produce a very small amount of light and high temperatures in the range of several thousand Kelvin within the collapsing bubble, although both the light and high temperatures are too weak and short-lived to be detected without advanced scientific equipment. The light emission and temperature increase probably have no biological significance but are rather side-effects of the rapid snapping motion. Pistol shrimp produce this effect in a very similar manner."

Glowing parrots!

Second post, sorry! I wanted to post about the awesomeness of glowing parrots.

"There is another pigment (or pigments) that have been reported only in parrots. These, rather than carotenoids, produce the yellows, oranges and reds. There are two types of yellow, one of which has a fascinating property: it fluoresces under ultraviolet (UV) or black light. Although originally reported in 1937 (O. Völker, J. Ornithol. 85: 136-146), little work has been done on this unusual property since. This phenomenon can be seen in the accompanying 'before and after' photographs. One image shows the parrot under normal lighting, the other under UV. The UV photos were taken using a commercial UV light tube and a wooden box, with the room lights turned off."


And I took pictures of my own birds under UV. I can't find the original ones that my icon comes from, but my icon is my short-billed corella (bare-eyed cockatoo) under UV. Any areas that are yellow on her glow a peachy orange under UV. These pictures were taken in December last year.

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