|
|
|||
|
|
|||
| นิตยสาร สารคดี: ฉบับที่ ๒๑๗ เดือนมีนาคม ๒๕๔๖ | ISSN 0857-1538 | |||
|
|
|
| Story: Rattapun Pattanarangsun | |||
|
|||
 |
|
Sex is always the favorite topic of conversation among the zoo workers. Hot sex. Dull sex. Or sadistic sex that entails a trip to the hospital or even death. No, this is not about sex among the zoo workers, but rather sex among all kinds of animals. As 6 years of experience as a veterinarian of a zoo can attest, animal sex is not a topic of obsession, but rather an intriguing science essential for maintaining a healthy population of animals in a zoo. Sex leads to reproduction, but not all animals reproduce sexually. Because sex involves an exchange of genetic material between two parties, simple organisms that multiply by duplicating their own genetic code are considered to have asexual reproduction. Sponge, for example, can breed by creating new cells with the same genetic code and shape but smaller-a process called "budding". |
|
 |
More evolved animals have designated reproductive cells that are divided into male and female and each contain half of the animal's genetic code. Generally the more highly evolved the animals, the more complex their reproductive systems are. Some high-level vertebrates have very complex hormone systems as well as behavioral patterns that are intricately linked to the working of the body in order for a successful insemination to happen. Science aside, what is really interesting about animal sex is the variety of styles and techniques employed by different animals. Among those worthy of mention is earthworm, the true bisexual. With both female and male organs-at the head- and tail-ends respectively-two earthworms copulate by doing a "69" pose. Snapper fish, on the other hand, change sex from male to female at a certain age. For seahorses, the female does the courting and squirting while the male bears the offspring. |
||
 |
In addition to unorthodox sex lives, some animals also have unusual tastes for romance. For some grasshoppers, the male has to sacrifice its dear life for sex because the female eats off the male's head as it ejaculates. Banded linsangs (a mammal) communicate romantic messages through their dung. White rhinoceros will not mate until they are dead tired from chasing each other around. For birds of paradise, the males would gather and show off their beauty so that the females can "shop" and choose the one they like to mate with. Despite the excitement and joy of sex, the question still remains: Why do 99.9% of high-level animals bother with the troubles of mating? Why not just simply eat and breed asexually? If the goal of life were to be fruitful and multiply, asexual reproduction would seem to do the job much better as it takes less energy and yields more results (number of offspring) in a much shorter time. |
||
 |
But the reality is: life on earth is difficult, filled with predators, competitors, and diseases. Asexual reproduction is good at passing on the same set of genes quickly, but the species cannot adapt so well to the ever-changing environment of the competitive world. On the contrary, sexual reproduction involves mixing and exchanging of genes from a greater gene pool. Through the process of natural selection, the animals within a given species that fit better given their environment have a better chance of surviving, mating and passing on their genes to the next generation. Though energy- and time-consuming, sexual reproduction in long run is better for survival of the species as a whole. There is thus more to sex than the joy of it after all. |