A Weapon of Distinction

 Attention is always given to the large predators who overpower their prey with brute force and ferocity. Great white sharks that launch themselves meters into the air as they attack seals from below, or a 6-metre Nile crocodile throwing itself out of the water to drag a 700kg buffalo to a watery grave. These great feats of strength and aggression provide a spectacle, and people look on at these scenes through their television with a mixture of fear and awe. This blog will not be about these barbaric and ferocious methods of hunting. Instead, it will focus on the evolution of an adaption for killing that is infinitely more complex, and infinitely more devious. Venom.

Venom can be described as a formidable mixture of complex molecules that, once injected into a victim's body, can attack the blood, muscle tissue or nervous system in order to kill, paralyse or otherwise incapacitate the  unfortunate receiving organism. It is markedly different from the term "poison" in that poison is ingested or absorbed, while venom is administered directly into the body through physical structures adapted for the task such as fangs, spurs or spines.  

The venomous spines of a Stonefish.

Venom has emerged as a highly effective chemical weapon in many organisms.  To compare the use of venom to the tools used by apex predators mentioned earlier,  you could just as well compare a sundial to a Rolex watch. Yes they both tell the time, however a sundial is simple and direct, while the watch is an elegant, intricate and often mind-boggling blend of cogs, gears, and of course, no small measure of witchcraft.

 A testament to the effectiveness of venom is the fact that it has evolved independently in reptiles, insects, mammals, fish, cephalapods and Cnidarians. While the mechanism of envenomation and type of venom varies between these animals, the basic theory behind the use of venom remains the same. 
The main advantage of venom, besides its lethal effectiveness, is the fact that, unlike poison, it can be used as a defence mechanism against predators as well as a hunting aid. It would also do well to point out that its use for defence does not require being ingested by the predator in order to be effective. 


Sources:
 http://en.wikipedia.org/wiki/List_of_venomous_animals - Accessed 8MAR14

Image:
http://jaredbullock.files.wordpress.com/2012/03/stonefish1.jpg -Accessed 8MAR14