http://www.night-vision-4you.com/ Night Vision Scopes, Goggles, Binoculars and Monoculars by ATN en-us Copyright (c) 2002 - 2008 night-vision-4you.com general@night-vision-4you.com webmaster@night-vision-4you.com Sat, 22 Nov 2008 09:00:47 GMT Night Vision news http://www.night-vision-4you.com/night-vision-news/11 Night vision Equipment by ATN in Moscow now. http://www.night-vision-4you.com/night-vision-news/11 general@night-vision-4you.com Night Vision news 2006-03-29 http://www.night-vision-4you.com/night-vision-news/10 Defense and homeland security companies Markland Technologies Inc. and Technest Holding Inc. report the Armys Night Vision and Electronic Sensors Directorate has awarded subsidiary EOIR Technologies Inc. new orders totaling 1.3 million. Awards to Virginia-based EOIR since July 15 total 9.5 million. The orders support combat and anti-terrorism operations in Iraq, said Robert Tarini, chairman and chief executive officer of Markland, which is based in Ridgefield, Conn. EOIR focuses on remote sensor systems and night vision technology and services. The 1.3 million in new orders arrives under the NVESD omnibus contract. The ongoing contract can provide a maximum of 80 million in fiscal year revenues, according to the company. http://www.night-vision-4you.com/night-vision-news/10 general@night-vision-4you.com Night Vision news 2005-09-15 http://www.night-vision-4you.com/night-vision-news/2 Predator calling with night vision optics is not only productive - its a lot of fun. I have called predators for the better part of 20 years, but almost always in daylight. It wasnt until several years ago, that I started calling them at night. The cover of darkness adds another level to this already challenging sport. On the plus side, predators are abundant at night and readily come to the call, but the obvious downside is they are hard to see. I have experimented with various spotlight, and gun mounted lights, and while they do work well under most situation, you have to lug around a bunch of battery packs and the occasional coyote will spook from the telltale glare of an uncovered light. When night vision optics first entered the market at an affordable price, I rushed out and bought one with preconceived notions of how well it would work for predators. To my dismay this inexpensive, first generation night vision wasnt very good. It didnt gather enough light, the image was very grainy and it required constant focusing to be able to see anything at all. I resigned it to the back of my gear closet and kept night hunting with my tried and true spotlights - even with their inherent faults. In the back of my mind though I always wondered how a high-quality night scope would work for predators. Recently I had the opportunity to find out. I tested ATNs newest Generation III night vision riflescope, the 7900 Crusader, and the comparison to my previous scope was like night and day. I mounted the ATN on an Armalite M15A4(T) with a stainless bull barrel and flattop receiver. The gun is a sub minute-of-angle, tack-driver that makes a perfect testing platform for this scope as the integrated Weaver-style base on the ATN will slip right onto the Armalite with no need for a separate mount or any modification.The first thing I noticed about the ATN scope was how bright and crystal clear the optics were. At all distances, the optics could quickly and easily be focused for precise viewing. Next to light intensifying, clarity is the hallmark of a quality night scope. To use the scope in the day, the ATN night scope has an integrated scope cap with a pinhole in the center, which provides enough light for use in broad daylight without damaging the scope with overexposure. I set a target at 50 yards and fired a three-shot group. All three shots literally touched. Moving the target out to 100 yards, I fired another three-shot group that measured an inch - a great testament to the rifle as well as the scope. The scopes reticle is a red illuminated crosshair with vertical holdover points and is adjustable for intensity with an easy to adjust knob located on the right hand side of the scope. The windage and elevation dials are finger-adjustable, but were stiff enough on the test model I reviewed to necessitate a coin or a small screwdriver. Once adjusted however, the scope did not shift point-of-aim during any of the testing which equaled a hundred shots and many miles on foot and in a vehicle over rough roads.Taking The ATN AfieldThe first night I took the ATN afield, it was a dark, cloudy night with no moon or stars visible, so I was a bit skeptical as to how the night scope would perform, as they do need some ambient light to perform well. The first time I shouldered the gun and pressed my eye to the shock-absorbing rubber eyecup of the scope, the field in front of me was lit up like a football field on homecoming night. I could easily shoot a coyote out to 100 yards and could see one approaching past 200 yards. The picture was crystal-clear and precise aiming wouldnt be a problem as the red crosshairs showed up well on the green background. I made two stands, but no coyotes made an appearance.The next night I took the ATN out again; it was a typical Nebraska night that makes Montana want to reconsider their state slogan - Nebraska truly is Big Sky Country- the moon was full and every star was shining bright. I sat down, started calling and turned on the scope. When I first looked through it, the previous nights amp;quot;great amp;quot; performance paled by comparison. I could spot a coyote out to 500 yards and could easily shoot to 200 yards - more than far enough for any predator-calling situation. After two stands I picked up movement out past 300 yards. Within seconds, the movement grew into a clearly defined coyote running towards my position. By the time the coyote got to 100 yards he was in focus and crystal-clear. At 75 yards I barked once with my Zepp 1080 open reed call and the coyote stopped in his tracks. The red crosshairs hovered on the chest and I squeezed the trigger. A momentary muzzle flash was visible through the scope then was gone - in its wake, lay a dead coyote. In addition to making a great line of night vision Optics, ATN also pioneered IR illuminator devices for aiding in low and no-light situations. I tested the integrated IR illuminator on top of the Crusader and the results were likewise incredible. The illuminator acts like an invisible spot light out to roughly 150 yards, lighting up everything for crystal-clear aiming and precise shot placement.After testing the ATN 7900 Crusader, I was glad I didnt let my previous poor experience with night vision cloud my judgment. There is a big difference between professional night vision devices like the ATN line of products and devices that merely allow one to amp;quot;kind of amp;quot; see in the dark. The 7900 Crusader elevates the sport of night predator calling and puts the hunter and predator on even terms. You can bet I wont be heading afield this winter without an ATN on my rifle.Click this link for more information about Night Vision. http://www.night-vision-4you.com/night-vision-news/2 general@night-vision-4you.com Night Vision news 2005-07-20 http://www.night-vision-4you.com/night-vision-news/1 Automatic Brightness Control (ABC)An electronic feature that automatically reduces voltages to the microchannel plate to keep the image intensifier amp;#8217;s brightness within optimal limits and protect the tube. The effect of this can be seen when rapidly changing from low-light to high-light conditions; the image gets brighter and then, after a momentary delay, suddenly dims to a constant level. BlackSpotsThese are cosmetic blemishes in the image intensifier or can be dirt or debris between the lenses. Black spots that are in the image intensifier do not affect the performance or reliability of a night vision device and some number of varying size are inherent in the manufacturing processes. Spots due to dirt or debris between the lenses should be removed by careful cleaning if the system is designed for interchanging optics. Bright-Source Protection (BSP)An electronic function that reduces the voltage to the photocathode when the night vision device is exposed to bright light sources such as room lights or car lights. BSP protects the image tube from damage and enhances its life; however, it also has the effect of lowering resolution when functioning. Cycles per Milliradian (cy/mr)Units used to measure system resolution. A milliradian is the angle created by 1 yard at a distance of 1,000 yards. This means that a device that can detect two 1/2-yard objects separated by 1/2 yard at 1,000 yards has a resolution of 1.0 cy/mr. Do not confuse cy/mr with line pair per millimeter. For example, a system can have a 3X lens attached and increase the system resolution by a factor of 3, yet the image intensifier amp;#8217;s resolution (measured in lp/mm) has not increased. DiopterThe unit of measure used to define eye correction or the refractive power of a lens. Usually adjustments to an optical eyepiece accommodates for differences in individual eyesight. Many military system provide a +2 to -6 diopter range. DistortionThree types of distortion are most significant to night vision devices: geometric, amp;quot;S amp;quot;, and sheer. Geometric distortion is inherent in all Gen 0 and Gen I image intensifiers and in some Gen II image intensifiers that use electrostatic rather than fiber-optic inversion of the image. Geometric distortion is eliminated in image tubes that use a microchannel plate and fiber optics for image inversion; however, some S-distortion can occur in these tubes. S-distortion results from the twisting operation in manufacturing fiber-optic inverters. Usually S-distortion is very small and is difficult to detect with the unaided eye, Gen III image tubes manufactured to U.S. military standards since 1988 have nearly no perceptible S-distortion. Sheer distortion can occur in any image tube that uses fiber-optic bundles for the phosphor screen. It appears as a cleavage or dislocation in a straight line viewed in the image area; as though the line were amp;quot;sheered. amp;quot; Non-inverting image intensifiers that use microchannel plates and clear glass for the optics are free of distortion. The image intensifier ITT manufactures for its Night Enforcer is distortion free. Equivalent Background Illumination (EBI)This is the amount of light you see in an image tube that is turned on but there is no light at all on the photocathode; it is affected by temperature where the warmer the night vision device, the brighter the background illumination. EBI is measured in lumens per square centimeter (Im/cm2) wherein the lower the value the better. The EBI level determines the lowest light level at which you can detect something and, below this light level, objects will be masked by the EBI. Emission PointA steady or fluctuating pinpoint of bright light in the image area that does not go away when all light is blocked from the objective lens. The position of an emission point within the field of view will not move. If an emission point disappears or is only faintly visible when viewing under brighter nighttime conditions, it is not indicative of a problem. If the emission point remains bright under all lighting conditions, the system needs to be repaired. Do not confuse an emission point with a point light source in the scene being viewed. Eye ReliefThe distance your eyes must be from the last element of an eyepiece in order to achieve the optimal image area. Fixed-Pattern Noise (FPN)A faint hexagonal (honeycomb) pattern throughout the image area that most often occurs under high-light conditions. This pattern is inherent in the structure of the microchannel plate and can be seen in virtually all Gen II and Gen III systems if the light level is high enough. Footcandle (fc)A unit of illuminance equal to one lumen per square foot. Footlambert (fL)A unit of brightness equal to one footcandle at a distance of one foot. GainAlso called brightness gain or luminance gain. This is the number of times a night vision device amplifies light input. It is usually measured as tube gain and system gain. Tube gain is measured as the light output (in fL) divided by the light input (in fc). This figure is usually seen in values of tens of thousands. If tube gain is pushed too high, the tube will be amp;quot;noisier amp;quot; and the signal-to-noise ratio may go down. U.S. military Gen II and Gen III image tubes operate at gains of between 20,000 and 37,000.On the other hand, system gain is measured as the light output (fL) divided by the light input (also fL) and is what the user actually sees. System gain is usually seen in the thousands. U.S. military systems operate at 2,000 to 3,000. In any night vision system, the tube gain is reduced by the system amp;#8217;s lenses and is affected by the quality of the optics or any filters; therefore, system gain is a more important measurement to the user. Gallium Arsenide (GaAs)The semiconductor material used in manufacturing the Gen III photocathode. GaAs photocathodes have a very high photosensitivity in the spectral region of about 450 to 950 nanometers (visible and near-infrared region). Generation 0Typically uses an S-1 photocathode with peak response in the blue-green region (with a photosensitivity of 60 uA/lm), electrostatic inversion, and electron acceleration to achieve gain. Consequently, Gen 0 tubes are characterized by the presence of geometric distortion and the need for active infrared illumination. Generation ITypically uses an S-20 photocathode (with photosensitivity of 180-200 uA/lm), electrostatic inversion, and electron acceleration to achieve gain. Because of higher photosensitivity, Gen I was the first truly passive image intensifier. Gen I is characterized by geometric distortion, poor performance at low light levels, and blooming. Generation IIUsually an S-25 (extended red) photocathode (with photosensitivity of 240+ uA/lm and a microchannel plate to achieve gain. Can be found with either electrostatic or fiber-optic inversion. Gen II tubes provide satisfactory performance at low light levels and exhibit low distortion. Generation IIIUses gallium-arsenide for the photocathode and a microchannel plate for gain. The microchannel plate is also coated with an ion barrier film to increase tube life. Produces more than 800 uA/lm in the 450 to 950 nanometer (near-infrared) region of the spectrum. Gen III provides very good to excellent low-light-level performance, long tube life. Recent mil-spec quality tubes have no perceptible distortion. Line Pairs per Millimeter (lp/mm)Units used to measure image intensifier resolution. Usually determined from a 1951 Air Force Resolving Power Test Target. The target is a series of different sized patterns composed of three horizontal and three vertical lines. You must be able to distinguish all the horizontal and vertical lines and the spaces between them to qualify for that pattern. LumenThe unit denoting the photons perceivable by the human eye in one second. Microamps per Lumen (uA/lm)The measure of electrical current (uA) produced by a photocathode when it is exposed to a measured amount of light (lumens). Microchannel Plate (MCP)A metal-coated glass disk that multiplies the electrons produced by the photocathode. An MCP is found only in Gen II and Gen III systems. These devices normally have anywhere from 2 to 6 million holes (or channels) in them. Electrons entering a channel strike the wall and knock off additional electrons which in turn knock off more electrons producing a cascading effect. MCPs eliminate the distortion characteristic of Gen 0 and Gen I systems. The number of holes in an MCP is a major factor in determining resolution. ITT amp;#8217;s new MCPs have 6.34 million holes or channels compared to the previous standard of 3.14 million. Milliamps per Watt (mA/W)The measure of electrical current (mA) produced by a photocathode when exposed to a specified wavelength of light at a given radiant power (watt). As with microamps per lumen, usually, the higher the value, the better the performance; however, it is important to know where in the spectrum the wavelength falls. Because more night light is present in the near-infrared region than in the visible or ultraviolet regions, a high value in the blue regions would not be a good as a moderate value in the near-infrared region. Near-InfraredThe shortest wavelengths of the infrared region, nominally 750 to 2,500 nanometers. Gen III operates from around 450 to 950 nanometers. PhotocathodeThe input surface of an image intensifier that absorbs light energy and in turn releases electrical energy in the form of an electron image. The type of material used is a distinguishing characteristic of the different generations of image intensifiers. Photoresponse (PR)See Photosensitivity. PhotosensitivityAlso called photocathode sensitivity. The ability of the photocathode material to produce an electrical response when subjected to light waves (photons). Usually measured in microamps of current per lumen of light (uA/lm). The higher the value, the better the ability to produce a visible image under darker conditions. ResolutionThe ability of an image intensifier or night vision system to distinguish between objects close together. Image intensifier resolution is measured in line pairs per millimeter (lp/mm) while system resolution is measured in cycles per milliradian. For any particular night vision system, the image intensifier resolution will remain constant while the system resolution can be affected by altering the objective or eyepiece optics by adding magnification or relay lenses. Often the resolution in the same night vision device is very different when measured at the center of the image and at the periphery of the image. This is especially important for devices selected for photography or video where the entire image resolution is important. Signal-to-Noise Ratio (SNR)A measure of the light signal reaching the eye divided by the perceived noise as seen by the eye. Atube amp;#8217;s SNR determines the low-light-resolution of the image tube; therefore, the higher the SNR, the better the ability of the tube to resolve objects with good contrast under low-light conditions. Because SNR is directly related to the photocathode amp;#8217;s sensitivity and also accounts for phosphor efficiency and MCP operating voltage, it is the best single indicator of an image intensifiers performance. ScintillationA faint, random, sparkling effect throughout the image area. Scintillation is a normal characteristic of microchannel plate image intensifiers and is more pronounced under low-light-level conditions. Sometimes called amp;quot;video noise. amp;quot; Do not confuse scintillation with emission points. SpectrumThe range of electromagnetic energy from cosmic rays to extra-low frequency used in submersed submarine communication. Electromagnetic frequency is measured in cycle per second and wavelength in microns or nanometers. The ultraviolet region extends from 100 to 400 nm with the near-ultraviolet nominally 300 to 400 nm. The visible portion of the spectrum extends from 400 to 750nm. The infrared region extends from 750 to 2xlO5 nm with the near-infrared nominally 750 to 2,500 nm. Evaluation Characteristics of night vision equipment fall into four major categories that help in evaluation: performance, human factors, suitability to its application, and the overall cost of ownership. If you have any questions, do not hesitate to call your local ITT dealer. Performance The very need for a night vision capability necessarily focuses on performance as the most important - Can you see a clear image when it is dark and you cannot see the scene or objects with your unaided eye? Most night vision equipment available today will provide an adequate image under higher night light conditions such as a full moon. Evaluate the following parameters to determine how well a system will perform when you need to see under truly dark conditions such as starlight. PhotosensitivityThe ability of a night vision system to detect light energy and convert it to an electron image is reflected in the image intensifier amp;#8217;s photosensitivity. Usually, the higher the value, the better the ability to amp;quot;see amp;quot; under darker and darker conditions. However, be aware that at night there is more light energy available in the near-infrared region than in the visible region. Therefore, if a device claims a high photosensitivity, make sure to find out where in the spectrum this is measured. A high photosensitivity in the blue or visible region may not perform as well as another system with a lower overall photosensitivity, but a higher value in the near-infrared region. Signal-to-Noise Ratio (SNR)This is probably the single most significant factor in determining a system amp;#8217;s ability to see when it gets dark. Be aware that SNR can be computed many ways to get desired results. Be sure to find out how SNR was computed. When measured according to U.S. mil specs, the SNR takes into account the photosensitivity, as well as the efficiency of the phosphor screen in reconverting the electron image to visible light and the amp;quot;noise amp;quot; contribution of the microchannel plate. Because the, SNR determines an image intensifier amp;#8217;s low-light-resolution, the higher the ratio, the clearer will be the signal compared to the background noise, hence, the better the ability to see under increasingly darker conditions. GainThis tends to be a confusing parameter when evaluating night vision devices. The most important gain measurement is the system gain. Very high gain values for an image tube are not especially significant - the U.S. military procures devices with the tube gain ranging from 20,000 to 37,000. Look for the system gain. U.S. military systems operate at 2,000 to 3,000. The higher the value the better the ability of the device to amplify the light it detects.A word of caution; gain is only part of the story. If a system does not possess a good photosensitivity and SNR, a very high gain value simply means that you will make a poor image brighter, not better. Also, very high gain values could mean the tube is driven very hard and the life of the tube will be reduced. The very best test is field evaluation under very dark conditions. ResolutionUsually this is measured as tube resolution (lp/mm) or system resolution (cy/mr). The more significant measurement is system resolution as this is what the viewer will actually experience and takes into account the quality of the system amp;#8217;s optics. If you are evaluating systems with similar optical quality and filters, the tube resolution is an important criteria. Resolution is often measured at high and low-light conditions. Most systems produce an optimal resolution at some point between very high light and very low light conditions.As long as resolution is measured the same way using the same magnification and the same conditions (i.e., per U.S. mil specs) the higher the value, the better the ability to present a sharp picture. However, be aware that many devices will produce a sharp image in the center of the viewing area, but less sharp as you look toward the periphery. The lack of a sharp image, except at the center of the viewing area, can be due to the presence of a Gen 0 image tube or to the system amp;#8217;s optics. Again, remember that many night vision systems will produce adequate results under higher night-light conditions, but perform poorly under darker conditions. Human Factors Here, such issues as weight, size, safe equipment, and the ease of operation should be considered. Remember that the ease of operation should be determined under dark conditions where the user cannot see the device being used. What may appear to be an acceptable level of operating ease under room lights may not be amp;quot;user friendly amp;quot; at all when it is dark. Protracted use should also be considered when evaluating weight. What may seem an acceptable weight when using a device for a short time, may not be so when viewing for long periods of time.Additionally, consider such functions as the on/power switch. Will you need to continually hold down the switch? - even light pressure for one finger for a long time can produce fatigue. Do you need to repeatedly press the switch to recharge the image tube? - such devices usually produce an initially bright image which gradually fades, reducing the ability to see and then shuts off unless you repress the switch. This characteristic could cause you to lose an image at a crucial moment. Suitability to its Application Within this category, characteristics such as field of view (FOV), magnification, versatility, weather resistance, and image distortion affect the ability of a night vision device to perform as needed. Magnification and FOVRegarding magnification and FOV, consider the distance you will need and the overall area you are observing or searching. For most surveillance or search applications, the higher the magnification or narrower the FOV, the greater the number of times you need to scan an area to avoid missing important objects or events. Usually a 1:1 lens with a 400 FOV provides optimal performance.For long range observation or weaponsight applications, the amount of magnification needed will vary; however, be sure to consider the other performance characteristics of the device; as the magnification increases, FOV decreases and the F number increases, all reducing the amount of light captured. Consequently, you will need an image tube with excellent performance at very low-light levels and/or high-performance lenses.Another factor involves the versatility of a device if it is used in situations that may require different magnification. How easily and quickly can the magnification be changed? Is it necessary to open the system to install the optics? In some cases, this may be inescapable, and the susceptibility of internal components to damage should be considered. DistortionGen 0, Gen I, and 25-mm Gen II electrostatically inverted image tubes produce a certain amount of geometric distortion in the image. In Gen III and 18-mm Gen II systems, geometric distortion is eliminated although it is possible to encounter some perceptible amp;quot;S amp;quot; and sheer distortion. The degree of any distortion and its interference with the application should be considered. When the application involves photography, video work, or weaponsights, the distortion and peripheral resolution are critical. Weather ResistanceThe ability of a night vision system to operate under adverse environmental conditions is another important factor. Any system built to U.S. mil specs for environmental factors will perform suitably under almost any condition encountered. The major concern is internal fogging that destroys the ability to see an image, hence, the ability to resist humidity and moisture is vital.In addition, when a night vision system is used on or around rivers or bodies of water, floatability can be a determining factor. ITT amp;#8217;s Night Enforcer 150/160 monoculars and 250/260 binoculars will float if dropped into water. Overall Cost of Ownership Evaluation factors that impact the actual cost of acquiring a night vision capability are image tube life (referred to as amp;quot;reliability amp;quot;), warranty coverage, repair availability, service support, and overall workmanship as an indicator of quality. When evaluating night vision equipment, the initial acquisition cost does not equate to the cost of ownership. How often will you need a new image tube? What is the likelihood for repairs? Are batteries available? What about exposure to bright lights?All image intensifiers will amp;quot;wear out amp;quot; over time due to gases generated within the tube that migrate to the photocathode and slowly kill it. Because of this, characteristics such as reliability, a bright-source protection (BSP) circuit, and the presence or absence of an ion-barrier film on the microchannel plate are important. U.S. mil specs describe procedures for projecting reliability. You should know what the reliability is for the tube you evaluate.An important factor that can influence reliability is the voltage used to produce gain. If an image tube is amp;quot;driven amp;quot; hard to produce high gain, it will accelerate the production of gases and more quickly kill the ability to convert light into electrons.A final evaluation criteria is to determine whether or not the night vision device incorporates automatic protection for the image intensifier when it is exposed to high-light conditions or bright-light sources. Image tubes manufactured by ITT have a BSP circuit built into the image intensifier. This circuit automatically reduces the voltage to the photocathode when the system is exposed to bright light sources. The BSP feature protects the image tube and enhances its life. If there is doubt, consult the warranty; does it exclude exposure to high light or bright lights? Note 1: Generation classification:Some night vision advertising has presented confusing information listing Russian equipment as Gen I, Gen II, and Gen III, when in fact, by worldwide classification it is Gen 0, Gen I, and Gen II, respectively. Note 2: Reconditioned Generation II:While the prices of amp;quot;reconditioned amp;quot; Gen II systems may be attractive, be aware that the hours of remaining life and photosensitivity performance cannot be restored to Gen II tubes. amp;quot;Reconditioned amp;quot; usually means the system has a new or repaired power supply but the photosensitivity will be lower, the SNR will be lower, and the remaining life will be less. Some reconditioned units may be operating at below acceptable minimums and few companies possess the necessary test equipment to evaluate the tube amp;#8217;s level of performance.The U.S. military specifications for Gen II require a reliability of 2,000 hours of operating time (ITT amp;#8217;s new Gen II image intensifier has tested to well beyond the military specification). This situation does not pertain to Gen III equipment. Due to the presence of an ion-barrier film in Gen III devices, the gallium-arsenide photocathode is protected from degradation and the life and performance are extended many times longer than Gen II. http://www.night-vision-4you.com/night-vision-news/1 general@night-vision-4you.com Night Vision news 2005-04-15 http://www.night-vision-4you.com/night-vision-news/3 Under the cloak of darkness in the worlds largest wetland in Brazil, the author experiences a chilling feeding frenzy EVER SO SLOWLY, unblinking red eyes glide along the silent black surface of the tropical swamp, like faintly glowing embers in the penumbra of dusk. Then, without warning, Clop! Massive toothy jaws snap shut the sound of an ancient reptilian dinner. Deep in the steamy interior of southern Brazil, the night belongs to the caimans and to the mosquitoes that are targeting this fair-skinned photographer, trying to stand still by her tripod. This is the Pantanal, a 40,000-square-mile, land-locked basin that makes up the worlds largest wetland ecosystem. Much of this area is flooded during the six-month rainy season from October to April, when its waters give birth to the mighty Paraguay River that empties into the Atlantic. Also hailed as the most wildlife-rich wetland in the Americas and arguably on the planet it is home to everything from tapirs, jaguars and giant otters to snail kites and jabiru storks. But none of the Pantanals wildlife has as colorful and checkered history as the caimans. Six of the worlds 21 species of Crocodilians are found in South America. The Paraguayan, or common, caiman is a smaller relative of the American alligator, reaching a length of ten feet at most. It is the widest ranging of the South American species; today, hundreds of thousands of the animals are found in the Pantanal. This was not always the case, however. Like the rest of the crocodile clan, the caiman has been heavily hunted by poachers for its hide. But the lowest point for the species came more recently than for most others because its smaller size and excessively bony skin made it less desirable to tanneries producing fancy leather goods for world markets. Fifteen years ago, even after protective legislation was passed in Brazil and international regulations were implemented to control trade in caiman skins, the Pantanal remained a hotbed for armed gangs of poachers and smugglers. An estimated one million caiman skins a year were being exported by the gangs. In response, the Pantanals land owners private cattle ranchers whose enormous holdings have produced beef since the late 1800s joined forces. Their aim was threefold: to protect themselves, their livestock and the wildlife that normally thrives on these private estates, many of which cover hundreds of thousands of acres. Banding together, the landowners succeeded in driving out most of the poachers, and today, with family ties in this expansive wilderness running back generations, many ranchers feel deep respect and attachment to the wild animals in their custody. Some have turned to ecotourism as a means of drawing attention to these riches. Roberto Klabin is one of them. His ranch at the very edge of the Pantanal, named the Caiman Ecological Refuge, receives wildlife enthusiasts like myself from around the world. amp;quot;Ten years ago you would have been lucky to see just one or two caimans in a week here, amp;quot; says Klabin, pointing at the many fat reptiles dozing on the lakeshore in front of his rambling ranch house. The timing of my Pantanal stay coincides with the early dry season in July, and everywhere ponds and waterways are shrinking as they begin to dry out in their annual cycle of renewal. For the caimans, which are remarkably adaptable to all sorts of habitat from open swamp to forested riverbank, this means finding a secure location where water will remain available until the next rainy season. Several dozen have taken up residence in a shallow watercourse serving as outflow to a large marshy lake, where I watch them daily. Only the tiniest of trickles still runs, but it is enough to govern the caimans day. I find their slow and unobtrusive lifestyle, virtually unchanged for at least 80 million years, utterly fascinating. With bone-plated hides and massive, crushing jaws, they make formidable predators. Their teeth are self-replacing and their stomach juices so potent possibly the most acidic of any animals in the world today they can digest every last morsel they swallow, bones, shell and all. Unlike mammals, their metabolism does not run in high gear, so they dont need constant food input to generate body heat. Instead, they can store energy as fat in their tails for months or even years between meals. The caimans have complex social lives where large males dominate smaller individuals, with postures and hierarchy helping them avoid dangerous and energy-draining fights. And unlike all other reptiles outside the crocodilian family, female caimans make devout mothers. They will guard their nests and young with their lives, responding to the cries of tiny hatchlings by digging them out of the warm fermenting vegetation mounds they build especially to incubate their eggs. Simply observing life at a caiman hole puts me into a time frame where the clock seems to tick far more slowly than elsewhere in the world. Not long after sunrise, the heat and humidity are already suffocating. But the caimans are in their element, heaped onto the sodden, spongy bank like so many flood-tossed rotting logs. They are basking in the sun to reach their preferred body temperature of 90 to 95 degrees F. Fifty or 60 strong, they lay so still they look like they could be made of stone, reminding me of the term amp;quot;living fossils, amp;quot; a nickname theyve earned for their ancient evolutionary history. Indeed, fossils show they have survived virtually unchanged since long before the dinosaurs went extinct. As the day grows hotter, one by one the caimans open their jaws wide to let airflow cool their moist maws. By noon the heat is unbearable. As I retreat to the shade of the forest, the caimans slither quietly into the tepid swamp water for a while, reemerging later in the afternoon. Only toward the end of the day does a sparkle of impending activity light up in their slit-eyed faces, even though they havent budged for hours. Now the whole of the Pantanal appears to awaken from its daytime stupor. With the setting sun turning crimson as it plunges through heavy layers of muggy air, elegant marsh deer emerge from the shadows to graze among the reeds, and giant anteaters scuttle across higher ground in search of termite mounds and ant nests. Collared fish eagles take up positions overlooking their favorite ponds and plumbous ibis probe the swamps for invertebrates. Ear-piercing flocks of emerald parakeets settle in the crowns of leafless pink blossoming trees, while the deeply raucous cries of electric blue hyacinth macaws proclaim their intention to feed on oily palm nuts. The caimans, too, are on the move, their rousing so gradual I hardly notice it at first. One by one they slither and glide toward the lake overflow where a thin film of water cascades down the embankment. They seem to know that with darkness tiny fish will be running downstream. Without shoving or jostling barely moving at all, in fact each of the creatures takes up a position in the current, mouth agape, letting the water and fish swirl through their formidable gleaming teeth. By the time the brief tropical dusk fades from gold to silver, and finally to hints of copper, the caimans form a perfect fan in the flow. They present a contiguous fanged barrage through which the fry must pass. Even the sound of the water flow has changed as it gurgles over and between row upon row of waiting teeth. Entire schools of small fish discover the trap too late, leaping frantically as jaws clamp shut at the slightest contact. It is an eerie scene, one I find all the more electrifying because of the contrast between the caimans day and night demeanor. From lazy daytime lounging, they are transformed into stealthy predators concentrating on their task with chilling purposefulness. Slipping off my boots, I tiptoe quietly into the shallow stream, facing the scene head-on. By staying in the darkest shadows, I manage to get within about six feet of the reptiles, with only a couple of them spotting me and retreating to deeper water. In my flashlight beam, dozens of caiman eyes shine as bright as rubies. Their pupils, now dilated wide and circular, give them visual acuity on par with owls. Deep into the night, the reptiles feeding frenzy on the tiny, two-inch fish continues. Clop, clop, clop. The incongruous primal feeding sounds mingle with other nocturnal cries and the incessant whine of swarming mosquitoes. Eventually, the bloodsucking insects, not the hungry reptiles, drive me away. By morning, on many a Pantanal stream bank like this one, caimans will once again be resting peacefully, back from the brink and here to stay. Information from http://www.nwf.org/nationalwildlife/article.cfm?articleId=734 amp;issueId=59 http://www.night-vision-4you.com/night-vision-news/3 general@night-vision-4you.com Night Vision news 2005-03-10