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| Sunday, 19 February 2006 |
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Junior Observer |  |
| News Business Features Editorial
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Amazing methods of attack and defence
The inhabitants of the animal kingdom have to be very adept (skilled) to survive in the wilds. They not only need to be skilled at hunting for food, which can be in the form of other animals, but also protect themselves from becoming prey to predators, which can be either animal or man. The techniques some of the animals use to attack and defend themselves can be amazing.
Some predatory animals seemingly possess the uncanny ability to hypnotize their prey, while others may have the power to paralyse them through methods that are similar to acupuncture. Then, there are animals that 'play dead' to keep prey at bay, shed limbs to escape from predators, and even squirt blood to ward off other animals when threatened with danger. Let us examine some of these extraordinary methods of behaviour today.
When hunting for food, some predatory animals use tactics similar to hypnosis. Some scientists call a particular behaviour of certain animals the 'dance of death'. This type of behaviour has been noticed among certain carnivorous mammals mostly mustelids which include stoats, weasels, martens, and foxes. Instead of pursuing its prey, the predator sometimes engages itself in an extraordinary display, leaping sideways and chasing its tail, so as to mesmerise the victim.
Throughout such a performance, the predator slowly edges closer to its prey, unnoticed by the victim. Then, suddenly, it will pounce, while the victim sits passively watching the bizarre performance, not knowing what to expect next. However, some scientists are divided as to whether the 'dance of death' is a voluntary performance, especially when it comes to stoats. Some researchers say it's due to a skull deformity caused by parasites that induces severe irritation and makes it dance, pointing out that these animals dance even in the absence of potential victims, while others say its dance is a ploy to attract victims, even some distance away. Meanwhile, there are animals who will achieve the same goal of hypnotizing their victims without exerting themselves by dancing or leaping... They simply use their powerful eyes to attract and mesmerise the victims.
The eyes of an Egyptian banded cobra are very powerful and magnetic. It could hold its intended victim in a state of suspended animation, and then suddenly sting, injecting its lethal venom. Even the Golden eagle has large, powerful eyes, which it uses to mesmerise other small animals. Scientists are once again divided in their opinion, but it is generally believed that the victims are so traumatised by the predator, that its escape instincts are inhibited (restrained), but not its curiosity. Owls are also believed to use this technique, but much research needs to be done in this area.
More than the methods used to attack potential victims, the techniques used by some of the animals to defend themselves are fascinating. Scientists have always been baffled by the way some animals, great and small, feign death, or enter into a trance to ward off predators. You may have heard of 'Playing Possum'. This term originated from the dramatic behaviour of the Virginian opossum (Didelphis marsupialis), which feigns death in the face of possible attack by a predator. This term is used to sum up the similar behaviour of other animals who also use the same technique of defence. Scientists call this thanatosis, after the Greek god of death, Thanatos.
When an opossum plays dead, it gives a truly amazing performance. After it fails to ward off a predator using its teeth or by its savage growling, it abruptly collapses and becomes totally limp. It lies on its side, with its head turned down, eyes closed, mouth gaping and the tongue lolling out. It even ejects a vile-smelling green liquid from its anal glands. Even if the predator attempts to bite or claw at it, the opposum doesn't even flinch and the predator eventually leaves, thinking it to be 'unpalatable'. Then, after a period of about six hours it gets back to normal.
However, research has revealed that not all opossums play dead or enter a thanatotic state. Only a few resort to this deceptive tactic, but many other animals, including various rodents, toads and frogs, different kinds of insects and even snakes, play dead as a defence mechanism. Among the insects that enter a thanatotic state are sexton beetles, stick insects, grasshoppers, longhorn beetles and matids. The snakes that are skilled performers of this deceptive art are grass snakes and the American hog-nosed snake. These snakes are said to feign death when attacked, by writhing and bleeding, as if they are severely injured and dying.
They even lie on their backs with their mouths inverted and bleeding,
giving the appearance that their heads are completely smashed. The
hog-nosed snake is said to even over-react, and turn completely on its
belly, even though snakes do not turn upside down when they are dying.
Even more bizarre behaviour is recorded when it comes to defence tactics
among animals. We will examine them next week. |
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