People diet to look more attractive. Fish diet to avoid being beaten up, thrown out of their social group, and getting eaten as a result. That is the fascinating conclusion of the latest research into fish behavior by a team of Australian scientists.
The research team have discovered that subordinate fish voluntarily diet to avoid challenging their larger competitors. “In studying gobies we noticed that only the largest two individuals, a male and female, had breeding(繁殖) rights within the group," explains Marian Wrong. “All other group members are nonbreeding females, each being 5-10% smaller than its next largest competitor. We wanted to find out how they maintain this precise size separation."
The reason for the size difference was easy to see. Once a subordinate fish grows to within 5-10% of the size of its larger competitor, it causes a fight which usually ends in the smaller goby being driven away from the group. More often than not, the evicted fish is then eaten up.
It appeared that the smaller fish were keeping themselves small in order to avoid challenging the boss fish. Whether they did so voluntarily, by restraining how much they ate, was not clear. The research team decided to do an experiment. They tried to fatten up some of the subordinate gobies to see what happened. To their surprise, the gobies simply refused the extra food they were offered, clearly preferring to remain small and avoid fights, over having a feast.
The discovery challenges the traditional scientific view of how boss individuals keep their position in a group. Previously it was thought that large individuals simply used their weight and size to threaten their subordinates and take more of the food for themselves, so keeping their competitors small.
While the habits of gobies may seem a little mysterious. Dr. Wong explains that understanding the relationships between boss and subordinate animals is important to understanding how hierarchical(等级的) societies remain stable.
The research has proved the fact that voluntary dieting is a habit far from exclusive to human.”As yet, we lack a complete understanding of how widespread the voluntary reduction of food intake is in nature," the researchers comment. “Data on human dieting suggests that, while humans generally diet to improve health or increase attractiveness, rarely does it improve long-term health and males regularly prefer females that are fatter than the females' own ideal."

People diet to look more attractive. Fish diet to avoid being beaten up, thrown out of their social group, and getting eaten as a result. That is the fascinating conclusion of the latest research into fish behavior by a team of Australian scientists.
人类节食是为了看上去更有吸引力，（而）鱼类节食是为了避免被打败、被群体抛弃、甚至最终被吃掉。这是澳大利亚科学家最新研究鱼类行为而得出的迷人结论。

The research team have discovered that subordinate fish voluntarily diet to avoid challenging their larger competitors. “In studying gobies we noticed that only the largest two individuals, a male and female, had breeding(繁殖) rights within the group," explains Marian Wrong. “All other group members are nonbreeding females, each being 5-10% smaller than its next largest competitor. We wanted to find out how they maintain this precise size separation."
研究小组发现，低级鱼类自愿节食以避免挑战强大的对手。“在对沙鱼的研究中我们发现，只有两个大的个体——一雄一雌在种群中有繁殖的权利，”玛丽安·翁这样解释说，“其他所有群体成员都是不能繁殖的雌性，每一级都比其上一级小5%-10%。我们想知道为什么它们保持这样精确体型区别的原因。”

The reason for the size difference was easy to see. Once a subordinate fish grows to within 5-10% of the size of its larger competitor, it causes a fight which usually ends in the smaller goby being driven away from the group. More often than not, the evicted fish is then eaten up.
体型差异的原因显而易见。一旦低级鱼长到与其上级鱼类体型（差异）的5%-10%以内就会引起战争，而结果通常是小的沙鱼被群体抛弃。而且绝大多数时候，被驱逐的鱼类会被吃掉。

It appeared that the smaller fish were keeping themselves small in order to avoid challenging the boss fish. Whether they did so voluntarily, by restraining how much they ate, was not clear. The research team decided to do an experiment. They tried to fatten up some of the subordinate gobies to see what happened. To their surprise, the gobies simply refused the extra food they were offered, clearly preferring to remain small and avoid fights, over having a feast.
事实看表明，小鱼保持较小的体型就是为了避免挑战大鱼。它们这样做是出于自愿，还是因为食物数量受到限制，这个并不清楚。研究小组决定做一个实验，他们尽量喂大一些低级鱼，看看会有什么事情发生。让他们惊讶的是，低级鱼简单地就拒绝了他们提供的多余食物，更愿意保持小的体型以避免战斗，甚至成为大鱼的美餐。

The discovery challenges the traditional scientific view of how boss individuals keep their position in a group. Previously it was thought that large individuals simply used their weight and size to threaten their subordinates and take more of the food for themselves, so keeping their competitors small.
这个发现对于大的个体如何保证它们在群体中的地位的传统观点是个极大的挑战，以前都认为大的个体只是简单地利用自身的体重和（大的）体型来威胁低级鱼，从而为自己获得更多的食物以确保它们的竞争者体型较小。

While the habits of gobies may seem a little mysterious. Dr. Wong explains that understanding the relationships between boss and subordinate animals is important to understanding how hierarchical(等级的) societies remain stable.
尽管沙鱼的习惯看上去却有些神秘，翁博士解释说，理解了（种群中）大动物与小动物之间的关系对于我们理解等级社会如何保持稳定至关重要。

The research has proved the fact that voluntary dieting is a habit far from exclusive to human.”As yet, we lack a complete understanding of how widespread the voluntary reduction of food intake is in nature," the researchers comment. “Data on human dieting suggests that, while humans generally diet to improve health or increase attractiveness, rarely does it improve long-term health and males regularly prefer females that are fatter than the females' own ideal."
（这项）研究证明了这样一个事实，自愿节食并非人类独有的习惯。“尽管我们还没有彻底明白天生自愿减少食物吸收有多广泛，”研究人员说，“（但是）人类节食的数据表明，人类节食通常是为了促进健康或增加吸引力，（但）很少能保证长期的健康，并且男性一般希望女性能够比她们理想的那样再胖一点。”