Mats of the pelagic macroalgae Sargassum represent a complex environment for the study of marine camouflage at the air-sea interface. Endemic organisms have convergently evolved similar colors and patterns, but quantitative assessments of camouflage strategies are lacking. Here, spectral camouflage of two crab species (Portunus sayi and Planes minutus) was assessed using hyperspectral imagery (...

In 1999, Hoover and Kausik introduced a software token using the cryptographic camouflage technique and claimed that it can resist various on-line and off-line guessing attacks. Later, Kwon presented an authentication protocol based on the cryptographic camouflage technique and DSA, and pointed out that this initial protocol is vulnerable to an impersonation attack once a server’s secret key or...

Camouflage is widespread throughout the natural world and conceals animals from predators in a vast range of habitats. Because successful camouflage usually involves matching aspects of the background environment, species and populations should evolve appearances tuned to their local habitat, termed phenotype-environment associations. However, although this has been studied in various species, ...

Because the ability to hide in plain sight provides a major selective advantage to both prey and predator species, the emergence of the striking colouration of some animal species (such as many coral reef fish) represents an evolutionary conundrum that remains unsolved to date. Here I propose a framework by which conspicuous colours can emerge when the selective pressures for camouflage are rel...

Camouflage is the primary defense in cuttlefish. The rich repertoire of their body patterns can be categorized into three types: uniform, mottle, and disruptive. Several recent studies have characterized spatial features of substrates responsible for eliciting these body patterns on natural and artificial backgrounds. In the present study, we address the role of spatial scales of substrate text...

Cephalopods possess a sophisticated array of mechanisms to achieve camouflage in dynamic underwater environments. While active mechanisms such as chromatophore patterning and body posturing are well known, passive mechanisms such as manipulating light with highly evolved reflectors may also play an important role. To explore the contribution of passive mechanisms to cephalopod camouflage, we in...

Animals in the lower mesopelagic zone (600–1,000 m depth) of the oceans have converged on two major strategies for camouflage: transparency and red or black pigmentation [1]. Transparency conveys excellent camouflage under ambient light conditions, greatly reducing the conspicuous-ness of the animal's silhouette [1, 2]. Transparent tissues are seldom perfectly so, resulting in unavoidable inter...

A crucial problem for most animals is how to deal with multiple types of predator, which differ in their sensory capabilities and methods of prey detection. For animals capable of rapid colour change, one potential strategy is to change their appearance in relation to the threat posed by different predators. Here, we show that the dwarf chameleon, Bradypodion taeniabronchum, exhibits different ...

Hair is venerated, cherished, and desired in societies throughout the world. Both women and men express their individual identities through their hairstyles. Healthy hair contributes to successful social assimilation, employment, and overall quality of life. Therefore, hair loss can have detrimental effects on almost every aspect of a person's life. In this review, we discuss the myriad of opti...

Ocular reflectors enhance eye sensitivity in dim light, but can produce reflected eyeshine when illuminated. Most teleost fish occlude their reflectors during the day. The opposite is observed in cryptic sit-and-wait predators such as scorpionfish and toadfish, where reflectors are occluded at night and exposed during the day. This results in daytime eyeshine, proposed to enhance pupil camoufla...