Screamers: More Anatomical Anomalies
Summary: You mean Screamers have even more physical oddities? Yep! Join Kiersten to find out about more anatomical anomalies of Screamers.
For my hearing impaired followers, a complete transcript of this podcast follows the show notes on Podbean
Show Notes:
Ornithology 3rd Edition by Frank B. Gill
“A peculiar association: the skin and the subcutaneous diverticula of the Southern Screamer (Chauna torquata, Anserifomes), by Mariana B. J. Picasso, Maria Clelia Mosto, Romina Tozzi, Federico J. Degrange, and Claudio G. Barbeito. Vertebrate Zoology, 64(2): 245-249, 7/25/2014.
“A Study of the Pterylosis and Pneumaticity of the Screamer,” by Ida S. DeMay. The Condor, March 1940, vol 42.
Music written and performed by Katherine Camp
Transcript
(Piano music plays)
Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.
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Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating.
This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.
In this episode we will continue with our anatomical anomalies. The seventh thing I like about Screamers is their unusual feather pattern and subcutaneous air pockets. That is not a sentence I ever thought I would say, but I have had this experience many times since I’ve started Ten Things I Like About…
Just like the last episode, we will have to do a little bit of background on avian anatomy before we jump into the Screamer anomalies, so let’s get started.
Birds are covered in feathers. When talking about nature you should not use all or never because there is always an exception to the rule, but we can safely say that all birds have feathers. Feathers help bird do lots of different things such as keep warm, keep cool, keep hidden, or advertise their presence, and of course fly. They have different types of feathers that cover their body, such as flight feathers, both primary and secondary that help them fly, tail feathers that help them during flight and balance while perching, downy feathers that lay close to the skin to help with temperature regulation, and bristles that are often seen near the eye or mouth.
Feathers grow out of the skin from pores. They are not spread along the entire skin like the fur of most mammals. Avian feathers grow in tracts on the birds body. The concentration of the tracts can differ depending on the species of bird, for example, Tundra Swans, which have approximately 25,000 feathers, have 80% of those feathers on their head and neck, where as, songbirds have 2000 to 4000 feathers and only 30 to 40% are found on the head and neck. In between these track are patches of bare skin called apteria.
There are nine major feather tracts. These names of the feather tract are not important for our purposes, but where they are located is pertinent. On most birds the feather tracts travel from the middle of the head at the base of the beak down the spine to the tail. There are more tracts on the tops of the wings from shoulder to wrist, along the side of the neck and belly, and long the legs.
You may be thinking, “I have never seen big ‘ole bald spots on birds?” Well the feathers in the tracts lay flat and cover the apteria. That’s why we don’t see them. For any one you that have pet birds that you can handle and groom, know just what I’m talking about.
Okay, what does this have to do with our Screamers? Well, Screamer feathers do not grow in tracts like other birds. They grow all over their body. Screamers have no apteria, no patches of bare skin. Why? We don’t know. The other bird species that have this type of feather growth pattern are the flightless ratites including ostriches, emus, rheas, and cassowaries, as well as penguins, so what the flighted Screamers are doing with this pattern of feather growth, we’re not entirely sure. But it is one more thing that makes Screamers unique.
The second anatomical anomaly of Screamers that we are going to talk about in this episode is the odd subcutaneous air bubbles they possess. That is right, I said subcutaneous air bubbles. This is pretty odd, let’s delve into it.
First a bit of background into bird respiration. Birds do have lungs similar in structure to mammals but they function differently. Most bird species have two lungs attached to the trachea via two bronchi. Sounds pretty familiar, but the air flow is different. In mammals air flow is both in and out. Birds breathe in only one direction, but they have only one trachea. So how does this work?
Air sacs that are part of their respiratory system. These sacs allow birds to utilize all the oxygen in each breath and disperse carbon dioxide back into the atmosphere while employing continuous, unidirectional, efficient flow of air. Amazing! This respiratory system it what allows birds to process enough oxygen to fly and prevent them from overheating when they are in flight. Pretty important stuff.
Screamers have an oddity associated with their respiratory system. They have subcutaneous diverticula, also known as, pneumatic diverticula, subcutaneous air cells, or superficial air cavities, all over their body. These bubbles are full or air and lay between the skin and muscles. These structure appear to be extensions of their respiratory system.
Why do they have these extra air sacs? Once again, we don’t know. Screamers are a riddle wrapped in a mystery inside an enigma. But boy it does make them fun!
We can make educated guesses as to why they might need these, such as Screamers fly at unusually high altitudes and the excess air sacs ma y help in buoyancy keeping the body light. This combined with their highly pneumatic bones that we learned about in the last episode could explain the extra air sacs.
These subcutaneous air sacs may also help them extract as much oxygen out of thin air as possible. We do know that it gives them a strange crackling noise when they walk, and keeps them safe from hunters. The extra air sacs make them unappetizing to the human palate.
Well, that’s it for episode seven of Screamers and I hope you found it as fascinating as I did because my seventh favorite thing about them in their anatomical anomalies.
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Join me next week for another exciting episode about Screamers.
(Piano Music plays)
This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.
New Zealand