Well, 2013 has come to a close, and it’s the beginning of a new year.
A lot of stuff has happened for me last year. I went to a number of conferences and began outdooring more actively.
I also took a position at a university, teaching anatomy.
Some short term plans are in order for ArsAnatomica:
Inflating a set of cat lungs
Lungs are by most accounts mundane. Everybody has them, few give it much thought. But sequestered within darkness of the chest cavity, enveloping the fluttering heart, there’s an incredible wonder to this oddly inflatable organ.
Dissection is a destructive process. Rudely excised from membranous mooring and nourishing vessels, the deflated lungs appear little more than bloodied meat; amorphous and exposed…….until a breath of air unfurls its secret glory.
Here, a set of cat lungs is inflated with a straw. Comprised of hundreds of millions of microscopic air sacks called alveoli, mammalian lungs harbor air capacity that is difficult to believe unless seen. The color of the entire organ lightens into a soft pink, as each microscopic sac fills with air.
A debt of gratitude is owed to cyborgraptor for her assistance in creating these gifs, as well as the students that helped me film this demo.
Making drawings of an otter. This little girl died at a sanctuary and was borrowed from a friend for the day.
Outside of anatomy stuff, I also enjoy exploring. I met this nice young man on a walk a few months back.
He’s a Northern Elephant Seal.
On the pacific coast, elephant seals gather by the hundreds to breed on the beaches during winter. The males fight viciously for the coveted title of “Beachmaster”, the winners gathering large harems of females. Many will enter, but few win. Only the largest and most aggressive bulls have a chance, and the lesser bulls are driven to the edge of the colony or off the beach altogether.
This guy’s resting alone on a remote beach, evidently he lost. Although he’s not very large, he’s already got a nice collection of battle scars on his neck and chest (see 3rd photo). Impressive effort for a little guy…. He’ll make a fine beachmaster someday….
I take the opportunity to make some sketches.
I taught human anatomy for about two years at a college. Most of my students were just out of high school, bound for a pre-med or pre-nursing track.
After every arduous exam, I’d collect the notable answers to circulate, part humor, part cautionary tale.
Below is a selection of student errors collected from one such exam, copied from my email, as circulated to students:
Hey there! Thanks so much for your continued patronage. To be honest, I’m surprised that anyone still reads my blog after my year long hiatus.
A lot of things happened. I graduated from my program, losing access to my lab. After my brother passed away, I moved across the country and went to China several times. Right now, I’m having a hard time finding a job related to biology, so I’m working an office job in the meantime.
But all that’s irrelevant. The primary reason I stopped posting, was that, I lost sight of where I was going with this blog.
When I originally started, I was just posting random pictures from my life, interspersed with stuff like drawings, memes…etc. My life just happened to include a lot of morphology.
As time went on, the blog became more and more involved and “educational”, gaining “science outreach” status and thus drawing the attention of the academic and professional community. While this is a good thing, it also prompted a certain level of professionalism and quality, which I felt like I had a hard time living up to.
Now that my audience included not only tumblr users, but also government institutions, university professors and museum curators, etc, what do I write? How do I keep it interesting for both science professionals and general audience alike, and still have it be accessible? Should I strive for tumblr virality to reach more people, or write longer indepth articles that impart more information with less viral impact? Should I strive to educate at all? How much should I interact with the audience? Is it still appropriate to post interesting non-biology things or personal things?
These questions (and more),have kept me silent and conflicted for the past year. And throughout all this, I continued doing hundreds of dissections and skeletal prep, everything from chameleons, to tigers to sharks….etc.
I’m back. I don’t have any good answers, but not trying isn’t helping me. Moving forward, I’m going to try to strike a balance, between accessibility, audience, and purpose, and hopefully, I can still keep it MY blog, rather than a generalized anatomy/morphology infodump blog.
In the end, what I really want to do, is to reveal, acknowledge, and appreciate, this hidden world, that exists inside all living things. So beautifully alien, so intimately close and so breathtaking in its ingenuity.
Thanks again for your continued patronage…… lets go for a ride.
- Helen (ArsAnatomica)
I always felt that photos did poor justice to the breathtaking dimensionality of skulls, so lets try something different. (Making animated gifs is something I’m somewhat new at, so bear with me here.)
This is a Gaboon Viper skull.
Gaboons are large (highly-venomous) African vipers, that hold the unique distinction of having the longest fangs in the world, with the ability to inject more venom than any other snake. There’s usually two (or more) fangs on each side.
In the photo below, you can see a groove at the base of the foremost fangs, through which the venom duct enters the hollow fang.
Most people think of the skull as a single bone, with a detached lower law. In reality, the skull is comprised of a number of smaller bones that fuse during development. It’s a primitive feature, whispering through the proliferation of osteoclasts, of an ancient arms race and a story of segmented bodies gliding through endless silent seas.
These days, most mammals, birds etc, have fairly solid skulls, but the further you go down in the evolutionary latter, the looser skulls become.
Fish skulls are mostly still made up of loosely connected bones, that often breakdown into their components when cleaned for study. “Articulation” is art of making sense of it all and putting it all back together.
This is a Cutlass fish skull.
Cutlass fish are large eel-like fish that swim vertically, darting upwards to grab prey with their very large fangs.
Here’s a closeup of the fangs. They’re razor-sharp on the leading edge and barbed, making it difficult for prey to escape.
Due to their inherent flexibility, snakes have very loosely joined skulls that occassionally require assembly.
This is an eastern diamondback rattlesnake.
The skull of a Bengal tiger rests along side the skull of a domestic cat.
Notice the proportionally smaller braincase and eyes in the tiger, and the much larger flanges for muscle attachment, in comparison to the overall size of the skull.
As animals scale up in size, more muscle is needed to bear the additional weight and counteract the effects of gravity. To anchor the increased mass of the muscle, bones become more robust. Thicker, heavier, with larger flanges, and deeper hollows to provide the additional muscle with leverage.
It’s a cyclic system. More muscle is needed to support heavier bone which in turn supports more muscle…etc.
You’d think it could go on forever, but as animals become larger and more powerful, they also become heavier. For land predators, the cycle reaches a cutoff size when the increasing weight begins to negatively affect agility, maneuverability, and the ability to successfully catch prey.
While looking at the little screech owl, I took a series of photographs and made this gif to illustrate the of the automatic grasping action of the talons.
The structure of bird feet is set up so that the foot automatically grasps when the ankle joint is bent.
This automatic grip allow birds to sleep while perching, and for raptors clench/grasp prey as the leg is folded on impact.
The mechanism of the foot is ingenious…. there’s no muscle in there at all.
The foot is powered entirely by a pulley system of tendons.
Two tendons that run along the back of the leg, Flexor Digitorum Longus and Flexor Hallucis Longus are responsible for the automatic grasp. The former pulls the forward facing toes, and the latter pulls on the hallux, or back toe.
I drew a schematic diagram of these two tendons here:
It’s particularly interesting in raptors.
Raptors swoop down on prey with talons/legs outstretched. The impact with the prey folds the raptor’s legs against its body, causing the talons to clench automatically, tearing into the prey. The automatic grip is strong enough to kill, and is what allows many hawk species to catch and kill other birds in midair.
The ingenuity and perfection of this mechanism is mind-blowing.
Isn’t he cute? He looks almost alive.
Unfortunately, he’s not.
This little guy is an eastern screech owl. Following a heavy storm, he was found dead on a residential street, entangled in some fallen branches at the base of a utility pole.
I’ve previously posted a picture of him before. I’ve never had the opportunity to look at owls close up.
Since the eyes are fixed, owls move the entire head instead and can turn it almost all the way around.
There’s another lesser known effect of eye immobility. Owls have excellent vision but have close range astigmatism. The area just in front of them is always blurry.
But that’s okay, because that blind spot is covered by crines. Crines are specialized whisker-like feathers around the beak area that extend into the blurry zone.
These whiskers are highly sensitive, and allow the owl to “feel” for it’s food items, since it cannot see them.
The owl’s capacity for silent flight comes from the fimbriate border of it’s flight feathers. This comb-like edge breaks up turbulence over the wing to reduce sound.
These nubbins on his talons are called spicules, and are modified scales. Theyre common in birds of prey, and help improve grip by increasing the surface area, the same way fingerprints function in humans.
Owing to the circumstances in which he was found, we initially believed him to be another unfortunate motor vehicle victim, but soon realized that this was not the case.
There’s two blackened spots at the tips of his talons.
His underside is a charred mass of feathers, and he’s got a faint “burnt” smell. The skin on the inside of his leg is roasted to a golden brown. The word “rotisserie” comes to mind.
I guess that power line wasn’t a safe perch after all.
Can’t pass up the opportunity to make some more drawings.
A while ago, I was asked create a series of fact cards for Zoo Kingdom, a facebook game made by Blue Fang Games, the makers of Zoo Tycoon.
Each species introduced in the game, had a series of fact cards that aimed to introduce some aspects of their natural history, morphology and ecology.
I made about 150 of these. Below are my personal favorites.
Making sketches of an Eastern Screech-Owl …a sad power line fatality.
To use him to educate others, is the least we can do.
He’s a magnificent little creature.