Defense and Attack Strategies and Mechanisms in Biology - Biomimetics: Biologically Inspired Technologies - page 353

13.4.5 Smoke

A thick, disorienting ''cold smoke'' that can be generated in areas from 2,000 to 50,000 cubic feet. It
restricts an intruders eye-hand coordination and interactions among members of an intruding
group. White obscuring smoke can be delivered by grenades or smoke pots. Relatively inexpensive,
noncontaminating and tactically ideal for police use. Obscuring smokes are temporarily irritating
to the nose and throat and cause those affected to lose their senses of purpose and direction
(Alexander et al., 1996).
Compared to smell, all the intricate color and shape changes of the octopus are ineffective. One
way to counter this threat is to block the predator's sense of smell, which has been shown to be one
way in which the ink is used, though in large quantities. Obviously ink can be used to cover the
animal's hasty departure, but it can also be used as a decoy, since the octopus or cuttlefish can
produce a coherent plume of ink that is more or less of its own size and shape.

13.4.6 Stakes

A sharp stake, often of wood or bamboo, that is concealed in high grass, deep mud or pits. It is often
coated with excrement, and intended to wound and infect the feet of enemy soldiers. Can be utilized
both as a booby trap and as a barrier. Commonly known as punji stick or punji stakes (Alexander
et al., 1996).
The Komodo Dragon, Varanus komodoensis , the largest land-living lizard, feeds mainly on
carrion. Even though it is large and strong, mostly when it attacks living animals, it only wounds
rather than kills them. But even minor wounds often become septic, so septicemia seems to be a
significant mechanism for weakening and eventually killing prey. However, when the dragons fight
each other, they appear to suffer no ill effects, even though their fights are frequent and often result
in deep puncture wounds. If one could identify the bacteria in the dragon's saliva, including those
capable of killing its mammalian prey, then one might have not only a chemical weapon but also its
antidote. Additionally the wounds made by the dragon bleed profusely and it takes longer for the
blood to clot, so the saliva also contains an anticoagulant.

13.5 BIOTECHNICALS

13.5.1 Hypodermic Syringe or Dart

Modified shotgun or handgun in which the projectile is a drug-filled syringe activated by a small
charge on impact. Wide variety of drugs available including emetics (Alexander et al., 1996).
Organisms have two methods of delivering poison: externally (on being attacked) and internally
(on being eaten). Since plants can usually afford to lose a leaf or two, they tend to have the poisons
internally and are not necessarily brightly colored as warning. Animals are either brightly colored
(for instance, the poison-dart frogs, Dendrobates spp. or poisonous nudibranchs or insects, q.v.) or
carry their poisons in spines or stings. Bees, wasps, and scorpions are obvious examples of the
latter; the sting is deployed, penetrates the victim with effort from the stinger, and poison is injected
from a sac which contracts. In hive bees and presumably others, the sting sac also releases a
pheromone which attracts other bees and encourages them to sting — rather like a beacon or marker
used in bombing raids. The urticaceous hair found on stinging nettles ( Urtica spp.) and many
caterpillars is a passive mechanism. On the stinging nettle there are hollow hairs (Figure 13.5)
containing several irritating substances such as histamine (the mediator of some allergic reactions),
serotonin, acetylcholine, and formic acid. When lightly brushed against, the tip of the hair (made of
brittle silica) snaps off at an angle leaving a sharp tip that pierces the skin and delivers the cocktail.
A similar system operates in caterpillars. The urticating hairs or spines of the larva of the moth