Creature Corner, Vol. 6

Cuttlefish

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The last post sparked my interest in squids, but while researching squids I found a close cousin to be even more unique! Despite its name (derived from the Old Norse word for cushion?), the cuttlefish is not something I would be too keen to cuddle with. Like squids, cuttlefish have an ink sac, which secretes a characteristically brown ink to evade predators. Historically, that brown ink was used as a dye called sepia (thank goodness we have filters to tint our photos now, right?!).

For the record, cuttlefish aren’t even technically fish, they’re molluscs.

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While there are approximately 120 different species of cuttlefish, they are all characterized by the presence of a ‘cuttlebone’, which is a an internal, porous shell made of aragonite (better known as calcium carbonate). Cuttlebones are often given to caged birds such as parakeets as a source of dietary calcium.

 

They eat a fairly typical ocean diet: small molluscs, crabs, shrimp, etc., and they are preyed on by animals such as dolphins, sharks, fish, seals,  and seabirds. Humans are also known to eat cuttlefish.

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These guys inhabit shallow, tropical/temperate ocean waters ad can be found along the coasts of East & South Asia, Western Europe, the Mediterranean, and all coasts of Africa and Australia. Basically anywhere that isn’t the Americas.

Typically ranging in size from 15 to 25 cm (6 to 10 in), the largest species, Sepia apama, aka the Australian giant cuttlefish, has reached over 50 cm (20 in) in length and 10.5 kg (23 lb) is mass. See below:

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Recent studies indicate cuttlefish are among the most intelligent invertebrates; they also have one of the largest brain-to-body size ratios of all invertebrates.

Enough of the not-so-interesting, here’s what make cuttlefish really cool:

They have W-shaped pupils and have 2 spots of concentrated sensor cells on the retina, one to look more forward, and the other to look farther behind. Unlike mammals who focus their vision by reshaping the eye lens, a cuttlefish changes focus by shifting the position of the entire lens with respect to the retina. Wild. Cuttlefish have no blind spot since they can see forward and behind at the same time, and though they cannot perceive colors they do have an enhance perception of contrast.

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Instead of hemoglobin, red and iron-containing, cuttlefish have copper-containing hemocyanin pumping oxygen through their 3 seperate hearts (cuttlefish have 3 hearts!). This makes their blood a pretty cool greenish-blue colour.

The mating rituals of cuttlefish are pretty typical of aquatic creatures, HOWEVER, male cuttlefish avoid confrontation with other males by disguising themselves as females. They change their colouring, hide their extra set of arms (males have 4 pairs, females 3), and even pretend to be holding an egg sack.

A cuttlefish’s skin might be the coolest, and most intricate part. Like a chameleon, cuttlefish can rapidly change their skin colors. They also have the ability to change their skin texture, posture, and locomotion. All of this allows cuttlefish to communicate, camouflage, or warn off predators.

That was a lot of information to read so I’ll end this with a video showing a cuttlefish changing colours. It’s pretty trippy.

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Back in the Limelight

It’s been a long lime time since the last post, but here it is! So get your gin and tonic ready; the limes have arrived.

Have you ever wondered if limes float in water?
Probably not, but they do! (As long as they have a life jacket..)

Let’s demonstrate the beauty of buoyancy using two normal limes and two normal jars of water:

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These limes just float to the surface and just kind of bob around, so let’s skip ahead to where this gets interesting—

Same scenario: two limes, two jars of water; HOWEVER one lime is peeled, taking away it’s protective exterior.

Video CliffsNotes:

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The lime peel traps air in tiny pockets, which creates the buoyancy that pushes the lime upwards. Without that trapped air, the lime has no way to stay afloat. So always wear your lime life jacket!

Special thanks to my friends for the gift of inspiration
Song: Soco Amaretto Lime- Brand New

Womb Temperature

Things are warming up in science!
Last month a study was published involving eight lamb fetuses, in artificial wombs!

The artificial womb is essentially a clear plastic bag that is filled with a synthetic amniotic fluid. Attached to the bag is a mechanical placenta, a device that brings in nutrients, oxygen, and blood, as well as removes carbon dioxide and waste.

Over the span of 4 weeks, researchers observed lung and brain development, the lambs sprouted wool, opened their eyes, wiggled around, and even learned to swallow.

While this concept seems like something out of a Sci-Fi classic, researchers are actually hoping this technology will eventually benefit babies born prematurely.

Below is a video showing one of the lambs in the artificial womb:

 

 

For the Birds

While out in the field, I happened upon some aquatic birds—I believe they were Barrow’s Goldeneye ducks, which are thought to originally be from Iceland.

bgd*Note: I did not actually take this photo

My field companion managed to capture these alluring creatures on video while I provide commentary on the colour variations between sexes of birds:

 

Special thanks to my field companion for producing the video!( :

 

Charlie’s Magical Law

And for my next trick, I will attempt to move this red liquid through a glass tube using nothing but my hand!

(For about 22 seconds nothing really happens, but be patient!*)

Here’s the secret: The heat from my hand increased the temperature of the liquid just enough to create an increase of air pressure in the container; that increased air pressure is what pushes the liquid up through the tube. When the liquid is at the top of the container, air is then forced up the tube and cause the liquid to bubble. As the liquid cools so does the air pressure, causing the liquid to fall back down the tube.

And that’s the magic of Charles’s Law**!

*song in the video by Cherub
**the volume of a gas, at a constant pressure, expands as the temperature increases

 

Milk Paint

Can you paint with all the colours of the milk?

This activity is easy enough to do if you have some milk, food colouring, dish soap, a bowl, and a little stick. A heat source (microwave) is helpful as well.

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Pour some milk into the bowl and give it a little heat. I put mine in the microwave for 45 seconds. Then, add a few drops of food colouring!

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Apply a bit of dish soap to the stick, and dip it into the milk. This video shows what happens:

Have some fun swirling the stick through all the colours!

This one is a slowed-down video, which is pretty cool:

This happens because the grease-fighting soap is attacking the fat molecules in the milk, causing the motion. Since the soap doesn’t mix with the milk, it stays on the surface and spreads out. The food colouring makes this process easy to see, and way more cool!

Hologram

The future is here! Check out this video of a hologram I made:

This was accomplished by constructing a small projector-like device and setting on my phone. Seems simple enough, right?

The Supplies: graph paper, a rule, scissors, a pen, tape, a box cutter, CD cases, hot glue, and a smartphone.

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First Step: I measured out a trapezoid shape onto graph paper and cut it out as a guide. The references I found suggested using 1 cm x 3.5 cm x 6 cm measurements, but I ended up tweaking those a bit as I went along.

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Second Step: I traced that shape along the plastic part of the CD case, then used the box cutter to cut the plastic shape out; needing 4 pieces of plastic, I repeated this step a few times. This part was a little challenging, because the plastic kept breaking on places I didn’t want it to.

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Eventually I cut out four little trapezoids.

Third Step: I arranged the pieces into a pyramidal shape, and held them together momentarily with tape while I let the glue heat up. When it was ready, I glued the edged of the pieces together. The picture below gives a visual into what I just tried to describe.

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After the glue cooled, I was ready to try out the projector!

There are a bunch of cool videos to try on YouTube, the one from my video is here.

And here is the aftermath of the plastic cutting:

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