Three-Dimensional Camouflage: Exploiting Photons to Conceal Form
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On Visual Art and Camouflage
University of Northern Iowa UNI ScholarWorks Faculty Publications Faculty Work 1978 On Visual Art and Camouflage Roy R. Behrens University of Northern Iowa Let us know how access to this document benefits ouy Copyright ©1978 The MIT Press Follow this and additional works at: https://scholarworks.uni.edu/art_facpub Part of the Art and Design Commons Recommended Citation Behrens, Roy R., "On Visual Art and Camouflage" (1978). Faculty Publications. 7. https://scholarworks.uni.edu/art_facpub/7 This Article is brought to you for free and open access by the Faculty Work at UNI ScholarWorks. It has been accepted for inclusion in Faculty Publications by an authorized administrator of UNI ScholarWorks. For more information, please contact [email protected]. Leonardo. Vol. 11, pp. 203-204. 0024--094X/78/070 I -0203S02.00/0 6 Pergamon Press Ltd. 1978. Printed in Great Britain. ON VISUAL ART AND CAMOUFLAGE Roy R. Behrens* In a number of books on visual fine art and design [ 1, 21, countershading makes a 3-dimensional object seem flat, there is mention of the kinship between camouflage and while normal shading in flat paintings can make a painting, but no one has, to my knowledge, pursued it. I depicted object appear to be 3-dimensional. He also have intermittently researched this relationship for discussed the function of disruptive patterning, in which several years, and my initial observations have recently even the most brilliant colors may contribute to the been published [3]. Now I have been awarded a faculty destruction of an animal’s outline. While Thayer’s research grant from the Graduate School of the description of countershading is still respected, his book is University of Wisconsin-Milwaukee to pursue this considered somewhat fanciful because of exaggerated subject in depth. -
Toads Have Warts... and That's Good! | Nature Detectives | Summer 2021
Summer 2021 TOADS HAVE WARTS…AND THAT’S GOOD! Warts on your skin are not good. Warts can occur when a virus sneaks into human skin through a cut. A medicine gets rid of the virus and then it’s good-bye ugly wart. Toad warts look slightly like human warts, but toad warts and people warts are not one bit the same. Toad warts are natural bumps on a toad’s back. Toads have larger lumps behind their eyes. The bumps and lumps are glands. The glands produce a whitish goo that is a foul-tasting and smelly poison. The poison is a toad’s ultimate defense in a predator attack. It is toxic enough to kill small animals, if they swallow enough of it. The toxin can cause skin and eye irritation in humans. Some people used to think toad warts were contagious. Touching a toad can’t cause human warts, but licking a toad might make you sick! Toads have other defenses too. Their camouflage green/gray/brown colors blend perfectly into their surroundings. They can puff up with air to look bigger, and maybe less appetizing. Pull Out and Save Pull Out and Pick one up, and it might pee on your hand. Toads Travel, Frogs Swim Toads and frogs are amphibians with some similarities and quite a few differences. Amphibians spend all or part of their life in water. Frogs have moist, smooth skin that loses moisture easily. A toad’s dry, bumpy skin doesn’t lose water as easily as frog skin. Frogs are always in water or very near it, otherwise they quickly dehydrate and die. -
Adaptations for Survival: Symbioses, Camouflage & Mimicry
Adaptations for Survival: Symbioses, Camouflage & Mimicry OCN 201 Biology Lecture 11 http://www.berkeley.edu/news/media/releases/2005/03/24_octopus.shtml Symbiosis • Parasitism - negative effect on host • Commensalism - no effect on host • Mutualism - both parties benefit Often involves food but benefits may also include protection from predators, dispersal, or habitat Parasitism Leeches (Segmented Worms) Tongue Louse (Crustacean) Nematodes (Roundworms) Commensalism or Mutualism? Anemone shrimp http://magma.nationalgeographic.com/ Anemone fish http://www.scuba-equipment-usa.com/marine/APR04/ Mutualism Cleaner Shrimp and Eel http://magma.nationalgeographic.com/ Whale Barnacles & Lice What kinds of symbioses are these? Commensal Parasite Camouflage • Often important for predators and prey to avoid being seen • Predators to catch their prey and prey to hide from their predators • Camouflage: Passive or adaptive Passive Camouflage Countershading Sharks Birds Countershading coloration of the Caribbean reef shark © George Ryschkewitsch Fish JONATHAN CHESTER Mammals shiftingbaselines.org/blog/big_tuna.jpg http://www.nmfs.noaa.gov/pr/images/cetaceans/orca_spyhopping-noaa.jpg Passive Camouflage http://www.cspangler.com/images/photos/aquarium/weedy-sea-dragon2.jpg Adaptive Camouflage Camouflage by Accessorizing Decorator crab Friday Harbor Marine Health Observatory http://www.projectnoah.org/ Camouflage by Mimicry http://www.berkeley.edu/news/media/releases/2005/03/24_octopus.shtml Mimicry • Animals can gain protection (or even access to prey) by looking -
Naturally Occurring Fluorescence in Frogs
Naturally occurring fluorescence in frogs Carlos Taboadaa,b, Andrés E. Brunettic, Federico N. Pedronb,d, Fausto Carnevale Netoc, Darío A. Estrinb,d, Sara E. Barib, Lucía B. Chemese, Norberto Peporine Lopesc,1, María G. Lagoriob,d,1, and Julián Faivovicha,f,1 aDivisión Herpetología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad de Buenos Aires C1405DJR, Argentina; bInstituto de Química Física de los Materiales, Medio Ambiente y Energía, CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires C1428EHA, Argentina; cFaculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto SP 14040-903, Brazil; dDepartamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires C1428EHA, Argentina; eProtein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires-CONICET, Ciudad de Buenos Aires C1405BWE, Argentina; and fDepartamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad de Buenos Aires C1428EHA, Argentina Edited by Jerrold Meinwald, Cornell University, Ithaca, NY, and approved February 9, 2017 (received for review January 19, 2017) Fluorescence, the absorption of short-wavelength electromagnetic dorsum of living adults of both sexes (Fig. 1D). Both spectral radiation reemitted at longer wavelengths, has been suggested to profiles presented excitation maxima of 390−430 nm and emission play several biological roles in metazoans. This phenomenon is maxima at 450−470 nm (blue), with a shoulder at 505−515 nm uncommon in tetrapods, being restricted mostly to parrots and (green) giving an overall cyan coloration and showing no evident marine turtles. -
How Photons Start Vision DENIS BAYLOR Department of Neurobiology, Sherman Fairchild Science Building, Stanford University School of Medicine, Stanford, CA 94305
Proc. Natl. Acad. Sci. USA Vol. 93, pp. 560-565, January 1996 Colloquium Paper This paper was presented at a coUoquium entitled "Vision: From Photon to Perception," organized by John Dowling, Lubert Stryer (chair), and Torsten Wiesel, held May 20-22, 1995, at the National Academy of Sciences in Irvine, CA. How photons start vision DENIS BAYLOR Department of Neurobiology, Sherman Fairchild Science Building, Stanford University School of Medicine, Stanford, CA 94305 ABSTRACT Recent studies have elucidated how the ab- bipolar and horizontal cells. Light absorbed in the pigment acts sorption of a photon in a rod or cone cell leads to the to close cationic channels in the outer segment, causing the generation of the amplified neural signal that is transmitted surface membrane of the entire cell to hyperpolarize. The to higher-order visual neurons. Photoexcited visual pigment hyperpolarization relays visual information to the synaptic activates the GTP-binding protein transducin, which in turn terminal, where it slows ongoing transmitter release. The stimulates cGMP phosphodiesterase. This enzyme hydrolyzes cationic channels in the outer segment are controlled by the cGMP, allowing cGMP-gated cationic channels in the surface diffusible cytoplasmic ligand cGMP, which binds to channels membrane to close, hyperpolarize the cell, and modulate in darkness to hold them open. Light closes channels by transmitter release at the synaptic terminal. The kinetics of lowering the cytoplasmic concentration of cGMP. The steps reactions in the cGMP cascade limit the temporal resolution that link light absorption to channel closure in a rod are of the visual system as a whole, while statistical fluctuations illustrated schematically in Fig. -
Countershading Prevents Organisms Above, Seeing This the Ears Assist in Heat Loss As They Species Below (Due to Its Dark Are Highly Vascularised
Bilby Butterfly Camel Long eyelashes help to keep sand The pattern and appearance on The sense of hearing and smell is out of the eyes, and nostrils in this species is used as a deterrent strong in this species. Their ears the shape of slits to prevent sand for predators. The two spots can are used to regulate heat and from entering the nasal cavity. be mistaken for two large eyes assist in heat loss in the warm Additionally, this species urine by a predator, therefore avoiding climate is highly concentrated to reduce predation water loss Dolphin Elephant Eucalyptus Tree Countershading prevents organisms above, seeing this The ears assist in heat loss as they species below (due to its dark are highly vascularised. The large Leaves hang downward to prevent colour). Contrastingly, if a total surface area to volume ratio excessive exposure to sunlight, predator is beneath this species, helps this species to maximise which also reduces water loss they are unable to distinguish this heat loss species swimming above due to its light colour underneath Fennec Fox Hummingbird Kangaroo This species has a fur colour This species cools down and similar to its environment to The small size of this species, lowers its body temperature by camouflage itself from other and the shape of the beak allows licking their forearms, as they predators. Additionally the large this species to reach far into the have a large capillary network highly vascularised ears help flowers’ centre to feed on the close to the surface of their skin. to lower body temperature to nectar This species also uses their tail as prevent excessive heating a counterweight for balance Katydid Mangrove Leaf Monstera This species lives in rainforests. -
Factors Affecting Counterillumination As a Cryptic Strategy
Reference: Biol. Bull. 207: 1–16. (August 2004) © 2004 Marine Biological Laboratory Propagation and Perception of Bioluminescence: Factors Affecting Counterillumination as a Cryptic Strategy SO¨ NKE JOHNSEN1,*, EDITH A. WIDDER2, AND CURTIS D. MOBLEY3 1Biology Department, Duke University, Durham, North Carolina 27708; 2Marine Science Division, Harbor Branch Oceanographic Institution, Ft. Pierce, Florida 34946; and 3Sequoia Scientific Inc., Bellevue, Washington 98005 Abstract. Many deep-sea species, particularly crusta- was partially offset by the higher contrast attenuation at ceans, cephalopods, and fish, use photophores to illuminate shallow depths, which reduced the sighting distance of their ventral surfaces and thus disguise their silhouettes mismatches. This research has implications for the study of from predators viewing them from below. This strategy has spatial resolution, contrast sensitivity, and color discrimina- several potential limitations, two of which are examined tion in deep-sea visual systems. here. First, a predator with acute vision may be able to detect the individual photophores on the ventral surface. Introduction Second, a predator may be able to detect any mismatch between the spectrum of the bioluminescence and that of the Counterillumination is a common form of crypsis in the background light. The first limitation was examined by open ocean (Latz, 1995; Harper and Case, 1999; Widder, modeling the perceived images of the counterillumination 1999). Its prevalence is due to the fact that, because the of the squid Abralia veranyi and the myctophid fish Cera- downwelling light is orders of magnitude brighter than the toscopelus maderensis as a function of the distance and upwelling light, even an animal with white ventral colora- visual acuity of the viewer. -
Deceptive Coloration - Natureworks 01/04/20, 11:58 AM
Deceptive Coloration - NatureWorks 01/04/20, 11:58 AM Deceptive Coloration Deceptive coloration is when an organism's color Mimicry fools either its predators or its prey. There are two Some animals and plants look like other things -- types of deceptive coloration: camouflage and they mimic them. Mimicry is another type of mimicry. deceptive coloration. It can protect the mimic from Camouflage predators or hide the mimic from prey. If mimicry was a play, there would be three characters. The Model - the species or object that is copied. The Mimic - looks and acts like another species or object. The Dupe- the tricked predator or prey. The poisonous Camouflage helps an organism blend in with its coral snake surroundings. Camouflage can be colors or and the patterns or both. When organisms are harmless camouflaged, they are harder to find. This means king snake predators have to spend a longer time finding can look a them. That's a waste of energy! When a predator is lot alike. camouflaged, it makes it easier to sneak up on or Predators surprise its prey. will avoid Blending In: Stripes or Solids? the king snake because they think it is poisonous. This type There are of mimicry is called Batesian mimicry. In lots of Batesian mimicry a harmless species mimics a different toxic or dangerous species. examples of The viceroy butterfly and monarch butterfly were once thought to camouflage. Some colors and patterns help exhibit animals blend into areas with light and shadow. Batesian The tiger's stripes help it blend into tall grass. Its mimicry golden brown strips blend in with the grass and the where a dark brown and black stripes merge with darker harmless shadows. -
Antipredator Deception in Terrestrial Vertebrates
Current Zoology 60 (1): 16–25, 2014 Antipredator deception in terrestrial vertebrates Tim CARO* Department of Wildlife, Fish and Conservation Biology, and Center of Population Biology, University of California, Davis, CA 95616, USA Abstract Deceptive antipredator defense mechanisms fall into three categories: depriving predators of knowledge of prey’s presence, providing cues that deceive predators about prey handling, and dishonest signaling. Deceptive defenses in terrestrial vertebrates include aspects of crypsis such as background matching and countershading, visual and acoustic Batesian mimicry, active defenses that make animals seem more difficult to handle such as increase in apparent size and threats, feigning injury and death, distractive behaviours, and aspects of flight. After reviewing these defenses, I attempt a preliminary evaluation of which aspects of antipredator deception are most widespread in amphibians, reptiles, mammals and birds [Current Zoology 60 (1): 16 25, 2014]. Keywords Amphibians, Birds, Defenses, Dishonesty, Mammals, Prey, Reptiles 1 Introduction homeotherms may increase the distance between prey and the pursuing predator or dupe the predator about the In this paper I review forms of deceptive antipredator flight path trajectory, or both (FitzGibbon, 1990). defenses in terrestrial vertebrates, a topic that has been Last, an antipredator defense may be a dishonest largely ignored for 25 years (Pough, 1988). I limit my signal. Bradbury and Vehrencamp (2011) state that “true scope to terrestrial organisms because lighting condi- deception occurs when a sender produces a signal tions in water are different from those in the air and whose reception will benefit it at the expense of the antipredator strategies often differ in the two environ- receiver regardless of the condition with which the sig- ments. -
Crypsis Decreases with Elevation in a Lizard
diversity Article Crypsis Decreases with Elevation in a Lizard Gregorio Moreno-Rueda * , Laureano G. González-Granda, Senda Reguera, Francisco J. Zamora-Camacho and Elena Melero Departamento de Zoología, Facultad de Ciencias, Universidad de Granada, E-18071 Granada, Spain; [email protected] (L.G.G.-G.); [email protected] (S.R.); [email protected] (F.J.Z.-C.); [email protected] (E.M.) * Correspondence: [email protected] Received: 7 November 2019; Accepted: 5 December 2019; Published: 7 December 2019 Abstract: Predation usually selects for visual crypsis, the colour matching between an animal and its background. Geographic co-variation between animal and background colourations is well known, but how crypsis varies along elevational gradients remains unknown. We predict that dorsal colouration in the lizard Psammodromus algirus should covary with the colour of bare soil—where this lizard is mainly found—along a 2200 m elevational gradient in Sierra Nevada (SE Spain). Moreover, we predict that crypsis should decrease with elevation for two reasons: (1) Predation pressure typically decreases with elevation, and (2) at high elevation, dorsal colouration is under conflicting selection for both crypsis and thermoregulation. By means of standardised photographies of the substratum and colourimetric measurements of lizard dorsal skin, we tested the colour matching between lizard dorsum and background. We found that, along the gradient, lizard dorsal colouration covaried with the colouration of bare soil, but not with other background elements where the lizard is rarely detected. Moreover, supporting our prediction, the degree of crypsis against bare soil decreased with elevation. Hence, our findings suggest local adaptation for crypsis in this lizard along an elevational gradient, but this local adaptation would be hindered at high elevations. -
Stereopsis in Animals: Evolution, Function and Mechanisms Vivek Nityananda1,2,* and Jenny C
© 2017. Published by The Company of Biologists Ltd | Journal of Experimental Biology (2017) 220, 2502-2512 doi:10.1242/jeb.143883 REVIEW Stereopsis in animals: evolution, function and mechanisms Vivek Nityananda1,2,* and Jenny C. A. Read2 ABSTRACT In humans, stereopsis has become an attractive model system for Stereopsis is the computation of depth information from views understanding the link between neural activity and perception (Roe acquired simultaneously from different points in space. For many et al., 2007; Read, 2015a). We now have a good basic understanding years, stereopsis was thought to be confined to primates and other of the different processes of primate stereopsis and the brain areas mammals with front-facing eyes. However, stereopsis has now been involved (Cumming and DeAngelis, 2001). Yet we know little demonstrated in many other animals, including lateral-eyed prey about stereopsis in other species. Remarkably, stereopsis was not mammals, birds, amphibians and invertebrates. The diversity of demonstrated behaviourally in any non-human species until ’ animals known to have stereo vision allows us to begin to investigate 130 years after Wheatstone, with Bough s (1970) proof of ideas about its evolution and the underlying selective pressures in stereopsis in macaque monkeys. We now know that many different animals. It also further prompts the question of whether all different species have evolved some form of stereoscopic vision. animals have evolved essentially the same algorithms to implement However, with the exception of a few model taxa, including stereopsis. If so, this must be the best way to do stereo vision, and macaques, cats and barn owls, we know very little about the should be implemented by engineers in machine stereopsis. -
For Camouflage Concealment of Facilities
Technical Note 446 The Use of for Camouflage Concealment of Facilities April 2015 A drilling rig sits atop the Roan Plateau in western Colorado. (image courtesy of Richard Compton) Suggested citation: Bureau of Land Management. 2015. The Use of Color for Camouflage Concealment of Facilities. Tech Note 446. Bureau of Land Management, Washington Office, Washington, DC. Production services provided by: Bureau of Land Management National Operations Center Information and Publishing Services Section P.O. Box 25047 Denver, CO 80225 BLM/OC/ST-15/004+8400 Acknowledgments Bureau of Land Management Tammie Adams, Writer/Editor, National Operations Funding and sponsorship for this publication were Center, Colorado provided by the U.S. Department of Energy and the U.S. Department of the Interior, Bureau of Land Ray Brady, Manager, National Renewable Energy Management (BLM). Coordination Office Tom Lahti deserves special recognition for his leadership, Brad Cownover, BLM Chief Landscape Architect guidance, and analytical attention to detail during the (formerly), Washington Office critical periods of this project; Terry Del Bene for the Terry Del Bene, Archaeologist, Rock Springs Field idea and early efforts that led to this outcome; and Sherry Office, Wyoming (retired) Lahti for managing the project to completion. Jennifer Hare, Landscape Architect Intern, Special thanks is extended to Guy Cramer of Washington Office HyperStealth Biotechnology Corporation who graciously dedicated endless hours to the BLM, providing time, Kay Hopkins, Recreation Specialist,