Blowing In The Wind: Seeds & Fruits Dispersed By Wind

Like an endless army of parachutists released from an airplane, seeds and fruits travel the wind currents and gentle breezes of the earth, possibly colonizing a distant mountain slope or fertile valley. Literally hundreds of species in many plant families have adopted this remarkable method of dispersal, including a variety of ubiquitous plants that we recognize as "weeds." The answer to why some weedy composites (such as the European dandelion) have worldwide distributions is truly "blowing in the wind" (to quote from the Peter, Paul and Mary song). Some of the ingenious adaptations for this method of wind dispersal include seeds that resemble parachutes, helicopters and gliders. In fact, one species (see opening photo) reportedly inspired the design of some early aircraft. An astronomer friend of Mr. Wolffia once observed a strange formation of flying objects through his telescope. He was focusing on a squadron of tiny parachute seeds high above his house. And the entire plant body of wolffa (the world's smallest flowering plant) may be transported by powerful cyclonic storms. In the southeastern United States there are records of wolffia plant bodies less than one millimeter long being carried by a tornado, and they have even been reported in the water of melted hailstones.
For More Information browse this website: http://waynesword.palomar.edu/plfeb99.htm#misc

A streamlined torpedo shape helps flying fish generate enough speed to break the water’s surface, and large, wing-like pectoral fins help get them airborne.

Flying fish can be seen jumping out of warm ocean waters worldwide. Their streamlined torpedo shape helps them gather enough underwater speed to break the surface, and their large, wing-like pectoral fins get them airborne.

Flying fish are thought to have evolved this remarkable gliding ability to escape predators, of which they have many. Their pursuers include mackerel, tuna, swordfish, marlin, and other larger fish. For their sustenance, flying fish feed on a variety of foods, including plankton.

There are about 40 known species of flying fish. Beyond their useful pectoral fins, all have unevenly forked tails, with the lower lobe longer than the upper lobe. Many species have enlarged pelvic fins as well and are known as four-winged flying fish.

The process of taking flight, or gliding, begins by gaining great velocity underwater, about 37 miles (60 kilometers) per hour. Angling upward, the four-winged flying fish breaks the surface and begins to taxi by rapidly beating its tail while it is still beneath the surface. It then takes to the air, sometimes reaching heights over 4 feet (1.2 meters) and gliding long distances, up to 655 feet (200 meters). Once it nears the surface again, it can flap its tail and taxi without fully returning to the water. Capable of continuing its flight in such a manner, flying fish have been recorded stretching out their flights with consecutive glides spanning distances up to 1,312 feet (400 meters).

Flying fish are attracted to light, like a number of sea creatures, and fishermen take advantage of this with substantial results. Canoes, filled with enough water to sustain fish, but not enough to allow them to propel themselves out, are affixed with a luring light at night to capture flying fish by the dozens. There is currently no protection status on these animals.

DOD tries to uncover secret of flying snakes

By Marc Kaufman

Washington Post Staff Writer
Monday, November 22, 2010; 11:37 PM

An unusual breed of Asian snakes can glide long distances in the air, and the Department of Defense is funding research at Virginia Tech to find out why.

Most animals that glide do so with fixed wings or a wing-like part. But not the "flying snakes" of Southeast Asia, India and southern China - at least five members of the genus Chrysopelea.

As video of the reptiles show, they undulate from side to side, in almost an air-slithering, to create an aerodynamic system. It allows them to travel from the top of the biggest trees in the region (almost 200 feet high) to a spot about 780 feet away from the tree's trunk.

"Basically . . .they become one long wing," said John Socha, the Virginia Tech researcher who has traveled extensively in Asia to study the snakes and to film them.

"The snake is very active in the air, and you can kind of envision it as having multiple segments that become multiple wings," he said. "The leading edge becomes the trailer and then the trailer become the leading edge."

It gets stranger. During a technique not yet understood, some of the snakes can actually turn in air. What's more, they all take a flying leap off their perch to get airborne, then drop for a while to pick up speed before starting the motion that keeps them aloft much longer than they would otherwise.

Socha's initial research was sponsored by the National Geographic Society, but his most recent work and paper were funded by the Defense Advanced Research Projects Agency. The agency is involved in advanced military technologies of all kinds, and Socha said the physical dynamics of snake flight (and how other creatures stay in the air) is of great interest to the agency.

DARPA did not respond to an e-mail asking for more information. However, Socha's upcoming paper on the dynamics of gliding snakes in the journal Bioinspiration and Biomimetics does list DARPA as its financial sponsor.

Socha was a featured speaker Monday at the annual meeting of the American Physical Society Division of Fluid Dynamics.

The snakes, Socha said, spend most of their lives in the trees. They are between 2 and 3 feet long and about as wide as a finger. The larger snakes, he said, generally cannot glide as far as the smaller ones.

The snakes are mildly venomous, he said, but "won't hurt a human, though they can be fatal to a gecko."

While the prospect of a flying snake seems strange today, current scientific theory says that birds evolved from dinosaurs, which were reptiles.

Flying Tree Snake

Flying Tree Snake
Chrysopelea spp.

If you are lucky, you may spot this elegant snake warming itself quietly in a sunny spot at Sungei Buloh Nature Park. But you have to be sharp eyed as they are well camouflaged.

They are the largest of the Flying Snakes, so named because they are the only snakes that can move through the air. They don't actually fly or glide but instead, perform a sort of parachute jump.
Soaring Serpents: To do this, they "suck in their guts" to form a U-shaped half-cylinder along the entire length of their bodies. The outer edges of their belly scales are rigid while the central portion of their belly scales fold upwards. This concave surface acts like a parachute, and increases air resistance to prolong the "flight".

The snake has some degree of control, undulating through the air as if swimming, holding its tail rigidly upwards and twisting the tail from side to side for balance. In this way, they can cross as much as 100m, although they crash land clumsily. This allows them to cross long distances quickly, perhaps to catch prey, escape predators or simply to move around. They generally parachute from tree to tree, but sometimes from tree to ground. To achieve this feat, they first have to climb up a tall launch point, which is not a problem as they have ridged (keeled) belly scales to help them grip vertical surfaces.

Although a cornered snake can be aggressive, the few snakes that I have come across in the park are shy and retiring. If they are left alone and observed from a distance, they remain motionless or quietly go about their business. Their venom is mild, and affects only their small prey. Their fangs are short, located at the back of the mouth, and are not hypodermic-like; the venom is injected through grooves in the fangs. Thus, they can only inject venom into prey that is well inside their mouths. As such, they hunt small prey like lizards, frogs, birds and bats. They stalk or pursue the prey and bite them on the neck. Small prey may be killed by their strong crushing jaws. Flying Snakes are active during the day and are mostly found in trees rather than on the ground.

Breeding: Little is known about their breeding habits. They lay 6-11 eggs, hatchlings are 15-20cm long and have the same pattern as the adults but their colours are brighter.

Role in the habitat: Like other predators, they control the populations of their prey. They are also eaten by others higher up on the food chain.

Status and threats: Flying Tree Snakes are not endangered at present. They do not tame well and do poorly in captivity.

LINKS

• Flying Snake Home Page by Jake Socha, University of Chicago: frequently asked questions on the species, quick-time video clips of their flight, photos, maps of their distribution, taxonomic details, heck everything you wanted to know about flying snakes.
• Taxonomic List of Sri Lankan Snake Species: fact sheet on Chrysopelea ornata.

REFERENCES

• Merel J. Cox, Peter Paul van Dijk, Jarujin Nabhitabhata and Kumthorn Thirakhupt, "A Photographic Guide to Snakes and Other Reptiles of Peninsular Malaysia, Singapore and Thailand", New Holland, 1998 (p. 66-67: description, photo).
• Carl H Ernst and George R Zug, "Snakes in Question: Smithsonian Answer Book", Smithsonian Institution Press, 1996 (p.14-15: details on the mechanics of their flight).
• Kelvin K P Lim and Francis L K Lim, "A Guide to The Amphibians and Reptiles of Singapore", BP Science Centre, 1992 (p. 67-68: habits, habitat, photo).

Other Note:

Mangrove and wetland wildlife at
Sungei Buloh Nature Park

Main features: Long, thin; mildly venomous, rear-fanged. Reaches 1-1.2m.

Status in Singapore: Common.
World distribution: Lowland rainforests of South and Southeast Asia from India to Southern China and the Philippines, down the Malay peninsula to Indonesia.
Classification: Family Colubridae, Genus Chrysopelea.
There are 5 species of Flying Snakes: Golden Tree Snake (C. ornata); Paradise Tree Snake (C. paradisi): much less common, sometimes with reddish-orange spots; Twin-banded Tree Snake (C. pelias); C. rhodopleuron; C. taprobanica.

Flying Snake

Flying snakes flatten their bodies into a concave C shape to trap air as they fall. By undulating back and forth, they can actually make turns in the air.

The image of airborne snakes may seem like the stuff of nightmares (or a certain Hollywood movie), but in the jungles of South and Southeast Asia it is reality.

Flying snake is a misnomer, since, barring a strong updraft, these animals can’t actually gain altitude. They’re gliders, using the speed of free fall and contortions of their bodies to catch the air and generate lift.

Once thought to be more parachuters than gliders, recent scientific studies have revealed intricate details about how these limbless, tube-shaped creatures turn plummeting into piloting. To prepare for take-off, a flying snake will slither to the end of a branch, and dangle in a J shape. It propels itself from the branch with the lower half of its body, forms quickly into an S, and flattens to about twice its normal width, giving its normally round body a concave C shape, which can trap air. By undulating back and forth, the snake can actually make turns. Flying snakes are technically better gliders than their more popular mammalian equivalents, the flying squirrels.

There are five recognized species of flying snake, found from western India to the Indonesian archipelago. Knowledge of their behavior in the wild is limited, but they are thought to be highly arboreal, rarely descending from the canopy. The smallest species reach about 2 feet (61 centimeters) in length and the largest grow to 4 feet (1.2 meters).

Their diets are variable depending on their range, but they are known to eat rodents, lizards, frogs, birds, and bats. They are mildly venomous snakes, but their tiny, fixed rear fangs make them harmless to humans.

Scientists don’t know how often or exactly why flying snakes fly, but it’s likely they use their aerobatics to escape predators, to move from tree to tree without having to descend to the forest floor, and possibly even to hunt prey.

One species, the twin-barred tree snake, is thought to be rare in its range, but flying snakes are otherwise quite abundant and have no special conservation status.

Flying Fish

কয়েক দিন ধরে সাগরে নিম্নচাপ চলছে। জেলেরা উদ্বিগ্ন, সমুদ্রের গভীরে না গিয়ে কাছাকাছি মাছ ধরছেন। হঠাৎ পাখির মতো একঝাঁক মাছ উড়াল দিয়ে শূন্যে ভেসে উঠল। এদের কয়েকটি গিয়ে পড়ল জেলেদের জালে। জেলেদের আনন্দ আর দেখে কে। কক্সবাজারে জেলেদের কাছে এ প্রজাতির মাছ পাখি মাছ হিসেবে পরিচিতি। জেলেদের কাছে এ মাছ তেমন একটা পরিচিতি লাভ করেনি। এ পাখি মাছেরা হঠাৎ উড়ে এসে অথৈ সাগরের বিস্তীর্ণ জলরাশি মাতিয়ে রাখে। কক্সবাজারে বাঁকখালী নদী তীরের ফিশারি ঘাটে জেলেরা এদের নিয়ে এলো বিক্রির জন্য। সুস্বাদু এ মাছ চড়া দামে বিক্রয়ও হয়ে যায়।

সাগরে আমরা যদি কখনো কোনো মাছকে উড়তে দেখি নিশ্চয়ই আশ্চর্য হব। আবার কোনো অচিন পাখি মনে করে ভুলও করতে পারি। এ পাখিটি যখন পানির মধ্য থেকে হুট করে ভেসে ওঠে কিছুক্ষণ আকাশে উড়ে আবার পানিতে ডুব দেয় তখন নিঃসন্দেহে বলা যায়, এটা মাছই হবে, পাখি নয়। এদের ইংরেজি নাম ঋষুরহম ঋরংয বৈজ্ঞানিক নাম ঊীড়পড়বঃঁং চড়বপরষড়ঢ়ঃবৎঁং. মাছটি লম্বায় কয়েক ফুট হতে পারে। মাছের পৃষ্ঠদেশ হালকা নীল বর্ণের। অঙ্গদেশ এবং পার্শ্বদেশ রুপালি। বক্ষপাখনা দীর্ঘ, লাল গোলাকার ফোটা থাকে। এ মাছটি বক্ষপাখনা ছড়িয়ে দিয়ে ঘণ্টায় প্রায় ৩৫ মাইল বেগে আকাশে উড়তে পারে। আসলে কিন্তু সে পাখির মতো ডানা ঝাপটিয়ে উড়ে বেড়াতে পারে না বরং উঁচু স্থান থেকে মানুষ যেমন গ্লাইটারের সাহায্যে ভেসে বেড়ায়। এক্ষেত্রে পাখিটি মাছটিও তার বুকের দুটি পাখনাকে পাখির মতো ছড়িয়ে দিয়ে বলা যায় গ্লাইড করে। তবে গ্লাইডিংয়ের জন্য উঁচু স্থান থেকে যেমন লাফিয়ে পড়তে হয় এক্ষেত্রে পাখি মাছ তার লেজের প্রচণ্ড শক্তি দিয়ে নিজেকে পানির উপরে ছুড়ে দেয়। এ সময় মাছটি এর লেজকে সেকেন্ডে ৫০ বার মটরের মতো কাজ করে দেহকে শূন্যে ছুঁড়ে দেয়। মাছটি কিন্তু মনের আনন্দে শূন্যে ভেসে বেড়ায় না, বরং যখন সে শত্রু দ্বারা আক্রান্ত হয় তখনই জান বাঁচাতে এভাবে শূন্যে ভেসে বেড়ায়। এভাবে সে এক মিনিট উড়তে পারে। যদি বাতাসের গতি ভালো থাকে তবে প্রায় ১০-২০ ফুট উঁচুতে উড়তে পারে। এদের কোনো কোনো প্রজাতির শুধু বুকের পাশের দুটি ফিনকেই পাখার মতো কাজে লাগায় আবার কোনো প্রজাতি বক্ষ এবং শ্রেণী উভয় জোড়া পাখনাকেই উড়তে কাজে লাগায়। এরা মূলত সাগরে বসবাস করে। এদের শরীরে প্রচুর আঁইশ আছে। এরা প্রধানত অমেরুদণ্ডী প্রাণী এবং ছোট ছোট মাছ খেয়ে বেঁচে থাকে।

- আসাদুজ্জামান আসাদ

Source: bangladesh-pratidin, 13th December, 2010