The Sugar Glider

September 23, 2011 at 2:35 pm

Petaurus breviceps, more commonly referred to as the “Sugar Glider,” is a small marsupial found in Australia. On average Sugar Glides have the ability to glide approximately 50-150 meters. Sugar gliders have a squirrel-like body ending in a long tail. The heady is rather short and narrow. The hind feet are “syndactylus”, with two of the toes being partially fused together. They use their long tails for a control while they glide.

“Sugar gliders are named for a reason – they have a sweet tooth.” Their main source of sugar comes by tearing into its bark they can get at the sweet honey-like sap. They use their ability to glide to move from tree to tree, but sugar is not the only part of a Sugar Gliders diet. They are nocturnal animals that prey on larva and small insects, but Sugar Gliders also have many predators such as owls, foxes, cats and dogs. Therefore, we can conclude that the ability to glide is used both for predatory purpose and as a defense mechanism.

To glide effectively, a Sugar Glider will generate power by thrusting its hind legs off a tall tree and spread its limbs to reveal the patagium or membrane connected to each of the limbs. This allows it to generate enough lift force to keep it going. The thing I found most interesting was about the way Sugar Gliders land. When about 3 meters away from its target, the Sugar Glider brings its hind legs up close to the body and swoops upwards to make contact with all four limbs.

It is remarkable that an animal that has only a 12-15 cm body and a tail of equal proportion can glide through the air at such a great distance. If you want one as a pet, it is legal to have a Sugar Glider in all but four states: California, Hawaii, Alaska, and Massachusetts.

REFERENCES:
“Sugar Glider – Petaurus Breviceps.” Angelfire: Welcome to Angelfire. Web. 22 Sept. 2011. .

Extract, Bean. “Sugar Glider.” Science Daily: News & Articles in Science, Health, Environment & Technology. Web. 22 Sept. 2011. .

“Domestic Photo Tours and Workshops Catering to Digital Nature Photographers.” Web. 22 Sept. 2011. .

“Video — Sugar Gliders — National Geographic.” Video — Animals, Travel, Kids — National Geographic. Web. 22 Sept. 2011. .

By Shahil Patel | Posted in student post | Tagged | Comments (5)

The Flying Lizard

September 23, 2011 at 12:36 pm


The agamid genus Draco, also known as the Flying Lizard, is a gliding animal. Within Southeast Asia, there are many different species of Draco, but they all have the same physical adaptation of a patagium. A patagium is an extension of extra skin from the body that acts as a wing for gliding animals. What is unique about the patagium of the Flying Lizard is rather than extending from the arms to the legs, it is supported by ribs. The patagium is attached to dorsal thoracic ribs and these ribs are extended outward when the Draco glides.

Draco sumatranus also known as the Common Flying Lizard

Draco Sumatranus also known as the Common Flying Lizard http://terselubung.blogspot.com/2010/02/draco-sumatranus-naga-avatar-dalam.html

Like other gliding animal, the Flying Lizard uses gliding mechanics to get from tree to tree. It leaps from its high up location thus horizontally accelerating. From there, it extends its patagium. This creates lift, which increases with to air speed and is the force that counters gravity. Once enough lift is generated to counteract gravity a steady level glide can be achieved.

It has been observed that Flying Lizards have amazing maneuverability in the air. They have the ability to avoid obstacles mid glide, and they have even been observed pulling off barrel rolls. This ability comes from the fact that they have a flexible patagium and that they have precise control over the movement and bending of the patagium through contractions of the internal and external intercostal muscles as well as the external oblique muscles.

There are many different species of Draco. Research has shown that how these various species glide depends on their wing loading. The species with smaller wing loading have greater maneuverability because of better muscle control, and they have a wider range of potential glide angles allowing them to have a larger gliding range. The results of the research showed the larger species with wing loading greater than 16 N/m2 have glide angles ranging from 25-34 degrees compared to the smaller Draco whose glide angles ranged from 15-35 degrees. The larger species also have to jump from higher locations to generate greater velocity so they can have lift that is large enough counter their weight.

Overall the flying lizard is remarkable. Its flexible patagium that it is able to manipulate is an amazing piece of nature and something that scientist could use in developing flexible-winged aircrafts.

References:

Alexander, David. "Nature's Flyers: Birds, Insects, and the Biomechanics of Flight". page 46 (link to Google books); September 22, 2011

McGuire, Jimmy and Dudley, Robert, "The Biology in Flying Lizards(Genus Draco) and their Fossil Extant Analogs" Oxford Journals. September 22, 2011.

Dudley, Robert. McGuire, Jimmy."The Cost of Living Large: Comparative Performance in Flying Lizards (Agamidae: Draco)" Web. September 22, 2011 [pdf]

"Gliding in Draco lizards and tree snakes" Map Of Life. Web. September 22,2011

By Sam Nichols | Posted in student post | Tagged , | Comments (2)

Batman and Biomimetics

September 22, 2011 at 11:57 pm

This Two-Faced picture shows that while Penguins can't fly, this Colugo can. Now isn't that a Riddle. No Joke.

This Two-Faced picture shows that while Penguins can't fly, this Colugo can. Now isn't that a Riddle. No Joke.

Superman cannot be explained. He soars faster than a speeding bullet- and without aid. Iron Man can be described as an engineer. He built a high-tech suit to rocket him sky high. Batman however, uses neither high-tech suits or the power of radiation to fly. Batman has mastered biomimetics.

Biomimetics is the art of mimicking biology to design new technologies. The term was coined during the 1950s when scientists starting studying nerves in biological systems. Bruce Wayne was the first to apply the study of biomimetics towards fighting crime. How did he do so?

Wayne created a patagium for himself.

The patagium is the thin membrane of skin stretching from the fore legs to the hind legs on the Colugo pictured below Batman. This skin unfolds from the Colugo's body when gliding, and just like Batman's, folds away when on the ground.

However, Batman has yet to totally outsmart biology. The Colugo actually has more than just one patagium. It also has a propatagium (found between its neck and legs), a dactylopotagium (found in between its digits) and a uropotagium (the potagium between its two hindlegs).

Evolution has given the Colugo the best potagium possible for flight. Not only is the Colugo's entire body a giant airfoil, the fur on the patagium even contributes to the great aerodynamics. The patagium is covered with shorter fur than the rest of the body, reducing the total amount of aerodynamic drag. Batman, however, has avoided this problem altogether by not including fur on his outfit.

The patagium is truly one of evolution's great designs. It has allowed animals- burdened by gravity- to take to the sky. And now, the study of biomimetics is allowing humans to defy the force of gravity as well.

When asked about the design of his cape, Wayne commented, "I tried to capture the genius of nature in every aspect. The shape and thickness were crucial- we had to get the aerodynamics just right. And as for the fur, we chose not to include it. Fur just isn't in style anymore."

References

  • Patagium, FlyingSquirrels.com (http://www.flyingsquirrels.com/Anatomy/patagium.html)
  • Batman, DCComics.com (http://www.dccomics.com/sites/batman/)

By Stephen Deschamps | Posted in student post | Tagged , , | Comments (2)

Flight of the Malayan Colugo

September 22, 2011 at 7:02 pm

The Mayan Colugo (Galeopterus variegatus) is a small mammal, about 34-40 cm in length and 1-2kg, which inhabits the dense forests of Southeast Asia. Recently, it has been discovered that the Colugo is actually the closest living relative of primates, making it a hot topic in evolutionary biology. It is nocturnal and feeds on young leaves, requiring it to visit many trees in one night. This explains its unusual evolutionary adaption, it glides! By gliding it can visit many more trees in one night. The Malayan Colugo can leap out of a tree and glide up to 110 meters by using their highly developed, and relatively large, patageum.

A Colugo in flight

The Colugo has the most developed patageum of any gliding mammal. Not only does it reach from its arms to its legs, it also connects the arms, the neck, the legs, and the tail. Scientists, wishing to study the flight characteristics of the Colugo glued accelerometers to their backs, and collected some surprising data.

It turns out that the Colugo encounters equal or less landing forces when it has been flying for a long period of time in comparison with short flights. This seems counter intuitive, considering one would expect the animal’s speed to increase with time, yet there may be an interesting explanation.

Colugo Flying2

One hypothesis is that since the Colugo lands vertically on a tree the majority of the time, yet glides horizontally, it somehow uses its patageum to create aerodynamic forces that rotate it into a vertical position. As the animal rotates, it also decreases its approach speed, as it is now in a state of highly increased drag. It must start this rotation by adjusting the position of its patageum in some way.

The specific movement that causes this adjustment in aerodynamic forces is still unknown. Could an experiment in a controlled environment with high-speed cameras, similar to Professor Full’s air righting gecko experiment, be the key to discovering exactly how the Colugo maneuvers in the air?

References:

Norris, Scott.   “Flying Lemurs are Primates’ Closest Kin.” Nationalgeographic.com. National Geographic. Web. September 22, 2011. http://news.nationalgeographic.com/news/2007/11/071101-lemur-relative.html.

Byrnes, Greg, Lim, Norman, Spence, Andrew. “Take-off and landing kinetics of a free-ranging gliding mammal, the Malayan colugo (Galeopterus variegatus).” The Royal Society. Web. September 22, 2011. http://rspb.royalsocietypublishing.org/content/275/1638/1007.full

Than, Ker. “Flying Lemurs with “Backpacks” Reveal Secrets.” Nationalgeographic.com. Web. September 22, 2011. http://news.nationalgeographic.com/news/2008/02/080212-lemur-backpacks.html

“Gliding Colugos.” BBC.co.uk. BBC. Web. September 22, 2011. http://www.bbc.co.uk/nature/life/Sunda_Flying_Lemur#p0038s8x

By Alex Fredman | Posted in student post | Tagged , , | Comments (2)

The “Flying Squirrel”

September 22, 2011 at 5:09 pm

Though they are called "flying squirrels", they actually don't fly but glide. There are 43 known species of flying squirrels in the world. For example, the Northern Flying Squirrel which has a total length from 23 to 35.6 cm weighs from 100 to 167 g at adulthood. Observations taken have shown that it can glide a distance up to 30.8 m. On the other hand, the Giant flying squirrel has a body length from 30.5 to 58.5 cm, a tail length from 34.5 to 63.5 cm and weighs from 1000 to 2500 g. As for the Giant squirrel, it can perform a glide of up to 450 m. I have taken those two completely opposite examples of flying squirrels to show that even the smallest or the largest species  can glide. But then the most important and crucial question is: " How do they glide?"

Flying squirrels, just like the Draco lizards, have wing-like folds of skin called patagium which stretch from the forearms to the hind legs. According to research done by scientists, the patagium produces lift which allows the squirrel to glide.

In addition, squirrels have little flaps called winglets at the tip of their patagium which are similar to the winglets on the wings of an airplane. Normally, for an airplane, the winglets prevent the formation of vortices at the tips of the wings. Two problems that wing tip vortices create are an increase in drag forces on the aircraft and a possibility of flipping any airplane which encounters them. As such, by comparing those two winglets, scientists assume that a squirrel used its winglets to reduce drag and to stabilize and to control the glide.

Last but not least, flying squirrels also have a tail which acts as a steering organ, enabling them to change their course of flight in mid-air. However, all the above information about the functions of the "flying" organs are only theoretical  assumptions and no one has yet unraveled the true mechanism by which squirrels glide.

Here is a video of a simple plane named the "squirrel" which has been designed based on the anatomy of the flying squirrel. Note that the plane has square wings and winglets pointing upwards.

References

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By Jean-Marc Tsang | Posted in student post | Tagged , | Comments (1)