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A chart of the amount of venom expended by different snakes for different prey sizes.
Amount of venom expended per hit by large and medium rattlesnakes on large and small prey. This figure shows that rattlesnakes inject different amounts of venom depending on prey size. It supports the idea that rattlesnakes have control of some sort on the lethality of a bite. (Recreated from Hayes, Lavin-Murcio&Kardong 1995)

A chart of the relationship between color and attack rate of different snakes.
Percent of time solid colored model snakes were attacked compared to models of the same base color with viper patterns. This shows that predators learn to avoid venomous snakes without bright warning colors, in support of the hypothesis that bright colors are not necessary for a Batesian mimicry system (Recreated from Wüster et al. 2004).

In both these cases, the non venomous snake increases its survivability by mimicking the venomous snake to the point that predators think they are the same species (and therefore themselves venomous). They are very good examples because the mimic does not gain any conspicuous colors that would hinder it from catching prey or make it more likely to be spotted by would be predators. There are two other forms of defensive mimicry that are subtypes of Batesian mimicry called Mullerian mimicry and Mertensian mimicry , which are forms of defensive mimicry between multiple venomous species and are explained with the coral snake mimics in [link] .

Olfactory mimicry

Another possible type of defensive mimicry is olfactory mimicry . It has been shown in the past that a few plants mimic the smell of dead meat or female insects to attract pollinators into the flowers. However, many scientists were skeptical of the possibility for defensive mimicry based solely on olfactory cues without any visual ones. In 1975, James A. Czalpicki and his colleagues performed an experiment that showed olfactory mimicry could theoretically serve as a form of defense (Czalpicki, Porter,&Wilcoxon 1975). During the experiment, several garter snakes were divided into two groups. Members of both groups were mostly fed minnows, but they were also fed night crawler worms on occasion. The experimental group was given a small dose of lithium chloride, which would make them mildly ill, while the control group was injected with saline solution. The results showed that the experimental group later rejected minnows that were dipped in “night crawler surface extract” so they smelled like the worms, but didn’t reject regular minnows. The control group did not reject the minnows that smelled like worms. Also, as a further experiment, they ran the same test but included some minnows made to smell like salamanders, without injection of LiCl, which neither group rejected. This showed that the experimental group rejected the earlier minnows because they smelled specifically like night crawlers and not because they smelled different from their normal meals for the previous several weeks. It seems though, that there have not been any cases found in the wild were olfactory mimicry is used by a species specifically for defensive purposes to date.

Death feigning

Another interesting defensive mimicry behavior in snakes is the well known death feigning of American hognose snakes, Heterodon spp . When threatened, a hognose snake flips onto its back and starts writhing around as if it is about to die from serious illness. This is followed by bloating and excretion (Munyer 1967). The snakes perform this display in water as well as on land, but tend to move more quickly to bloating and stillness when in water. When flipped back upright, the snake immediately flips onto its back again and continues the bluff. But what evolutionary purpose does death feigning really have? One possible explanation, and the most likely for hognose snakes, is that feigning death in such a dramatic and disturbing way will make the predator think that the snake has a disease or parasites and will not eat it for that reason (Milius 2006). It has also been discussed with insect and fish species that feigning death can provide defense by way of the bad odor emitted by many species displaying this behavior or can even be a form of aggressive mimicry that lures unsuspecting scavengers near the organism, which then 'comes back to life' and eats them. Some cases of similar behavior have been misinterpreted as death feigning, but are actually a form of defense where the bloating of the individual just makes it hard to swallow.

Questions & Answers

do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
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Daniel
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Abigail
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s. Reply
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Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
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Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
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Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
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s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
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s.
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SUYASH Reply
for screen printed electrodes ?
SUYASH
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s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
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Damian Reply
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Cied
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Porter
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Porter
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Yasmin
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what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
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AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
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Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
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Prasenjit
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Mockingbird tales: readings in animal behavior. OpenStax CNX. Jan 12, 2011 Download for free at http://cnx.org/content/col11211/1.5
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