Anatomy of a shark attack

Abstract

The victim swam confidently and serenely in clear, tropical waters, unaware of the terror she was about to experience. Suddenly, she found herself in a desperate struggle for life. With every ounce of strength she could muster, she fought to free herself from the merciless predator which had, without provocation, violently attacked. Amidst all the thrashing, she suffered intense pain and yielded to an overwhelming force. Soon, she was plunged into an alien environment.· The attack was relentless. After a few moments of struggle, which must have seemed an eternity, she was unable to breathe, lost all control, and became totally helpless. In preagonal torment, she collapsed as the invincible super-predator ripped her appendages from her trunk, one by one. then, as abruptly as he began, the predator broke off the attack, probably to search for other victims. The vanquished victim was fortunate and died quickly from acute blood loss; other less fortunate victims had lingered for days before finally succumbing to their injuries. Sounds familiar? This gruesome scene is not isolated or rare. The scenario varies, but the ultimate outcome is usually the same, namely, death for the victim. This sequence of events occurs at least 100 million times annually, or approximately three times every second. These are accurate, but gruesome statistics, and it is time to consider why such genocidal atrocities are permitted. The victim in this real-life drama is the shark, and the attacker is a human being! To understand the scenario, it is useful to appreciate how each independently fits into the food web, as well as the relationship between the two. Sharks have occupied the oceans for at least 350 million years. All known species have adopted a life-history strategy which we call 'K -selected' [1]. This means that sharks are slow growing, slow maturing, and invest much parental energy in a few, well-formed offspring. This is in contrast to the life-history strategy called' r-selected,' the lifestyle evolved by most bony fishes [2,3]. (K and r are symbols used in the mathematical formula for describing the growth of a population over time). Teleosts (bony fishes) with r-selected life histories grow very quickly, mature early and produce many fragile offspring with very little investment in any individual offspring. Sharks are not the only K -selected animals in the seas. The K -selected lifestyle has been adopted by most, but not all, large vertebrates, such as whales, dolphins, and sea turtles, as well as terrestrial elephants and even human beings [3]. The K -selected lifehistory strategy has served sharks well for millions of years; otherwise, they would not occupy a position of predominance in the seas. While this strategy allows a species to