研究表明，普通人可能比大象還要胖

研究表明，普通人可能比大象還要胖

Elephants may be the largest land mammals on the planet, but new research reveals that the typical human is in fact flabbier than these colossal creatures. Appearing in the Journal of Experimental Biology, the new study sheds light on the health of captive Asian elephants, suggesting that their low reproductive rates may not be due to an excess of body fat.

大象可能是地球上最大的陸地哺乳動(dòng)物，但新的研究表明，典型的人類實(shí)際上比這些巨型動(dòng)物更松弛。這項(xiàng)發(fā)表在《實(shí)驗(yàn)生物學(xué)雜志》上的新研究揭示了圈養(yǎng)亞洲象的健康狀況，表明它們的低繁殖率可能不是由于身體脂肪過(guò)多。

Sadly, many captive populations of Asian elephants are not self-sustaining, leading to concern among biologists that obesity may be affecting the animals’ fertility. However, while it’s true that captive elephants generally tend to carry more body fat than their wild counterparts, the impact of this extra weight on the animals’ health has never been properly investigated.

遺憾的是，許多圈養(yǎng)的亞洲象種群無(wú)法自我維持，導(dǎo)致生物學(xué)家擔(dān)心肥胖可能會(huì)影響這種動(dòng)物的生育能力。然而，雖然圈養(yǎng)大象通常比野生大象攜帶更多的脂肪是事實(shí)，但這種額外的體重對(duì)動(dòng)物健康的影響從未得到過(guò)適當(dāng)?shù)恼{(diào)查。

A team of researchers, therefore, set out to measure exactly how much body fat captive Asian elephants carry relative to their body weight, in order to discern if they can really be labelled obese. Explaining the difficulty in making such a determination, study author Daniella Chusy said in a statement that “obesity is not clearly defined in humans, let alone elephants.”

因此，一組研究人員開始測(cè)量圈養(yǎng)亞洲象體內(nèi)的脂肪與體重的比例，以確定它們是否真的可以被貼上肥胖的標(biāo)簽。該研究的作者丹妮拉·楚希在一份聲明中解釋了做出這一決定的困難，她說(shuō):“人類肥胖的定義并不明確，更不用說(shuō)大象了。”

Benjamin Taub

In their write-up, the authors expand on this issue by explaining that “obesity is a social creation to describe people with high levels of adiposity, and was originally developed based on mortality data.” However, applying such a diagnosis to elephants is fraught with difficulty as “there are no data on the relationship between adiposity levels and mortality in elephants.”

在他們的文章中，作者進(jìn)一步解釋道:“肥胖是一種社會(huì)創(chuàng)造，用來(lái)描述高度肥胖的人，它最初是基于死亡率數(shù)據(jù)而產(chǎn)生的。”然而，將這種診斷應(yīng)用到大象身上困難重重，因?yàn)?ldquo;沒(méi)有關(guān)于大象肥胖水平和死亡率之間關(guān)系的數(shù)據(jù)。”

A total of 44 Asian from zoos across the US and Canada were included in the study, 35 of which were female while the remaining nine were male. To measure the animals’ body fat, the researchers fed them slices of bread that had been soaked in heavy water, which contains an isotope of hydrogen called deuterium.

來(lái)自美國(guó)和加拿大動(dòng)物園的44名亞洲人參與了這項(xiàng)研究，其中35名是女性，其余9名是男性。為了測(cè)量這些動(dòng)物的身體脂肪，研究人員讓它們吃在重水中浸泡過(guò)的面包片，重水中含有一種叫做氘的氫同位素。

Zookeepers collected blood samples from the elephants in order to allow the researchers to measure the levels of deuterium circulating in each animal’s serum. By subtracting the amount of water in an elephant’s blood from its total body weight, the team was able to determine each individual’s fat level.

動(dòng)物園管理員收集了大象的血液樣本，以便研究人員測(cè)量每只大象血清中循環(huán)的氘水平。通過(guò)從大象的總體重中減去血液中的水分，研究小組能夠確定每個(gè)大象的脂肪水平。

On average, male elephants were found to carry about 8.5 percent body fat while females carried around ten percent. By contrast, the average healthy person has a fat content of between six and 31 percent, meaning most of us have a higher ratio of fat to body weight than a captive Asian elephant.

平均而言，公象體內(nèi)脂肪含量約為8.5%，母象體內(nèi)脂肪含量約為10%。相比之下，正常人的平均脂肪含量在6%到31%之間，這意味著我們大多數(shù)人的脂肪與體重的比例比圈養(yǎng)的亞洲象還要高。

More importantly, results also revealed that the least fertile female elephants tended to be those with the lowest fat levels, suggesting that low reproductive rates are not caused by obesity. Rather, it seems that being underweight carries the greatest risk of infertility among female captive Asian elephants.

更重要的是，研究結(jié)果還揭示，最不具生育能力的母象往往是那些脂肪含量最低的，這表明低繁殖率不是由肥胖造成的。更確切地說(shuō)，在雌性圈養(yǎng)亞洲象中，體重過(guò)輕是導(dǎo)致不孕的最大風(fēng)險(xiǎn)。

Furthermore, observations revealed that the elephants in the study tended to walk between 0.03 and 2.8 kilometers an hour. Previous research has found that wild Asian elephants generally walk between 0.01 and 1.15 kilometers per hour, indicating that the extra weight carried by captive elephants is not due to inactivity.

此外，觀察顯示，研究中的大象往往以每小時(shí)0.03到2.8公里的速度行走。此前的研究發(fā)現(xiàn)，野生亞洲象的行走速度一般在每小時(shí)0.01到1.15公里之間，這表明圈養(yǎng)大象攜帶的額外重量并非由于不活動(dòng)。

Finally, the researchers report that insulin levels tended to be higher among the fattest elephants, raising concerns that some may run the risk of developing diabetes-like symptoms. Overall, the study authors tentatively suggest that elephants with a fat content of more than 14 percent could be considered obese, as this threshold was associated with elevated levels of blood insulin.

最后，研究人員報(bào)告說(shuō)，最胖的大象體內(nèi)的胰島素水平往往更高，這引起了人們的擔(dān)憂，有些大象可能會(huì)出現(xiàn)類似糖尿病的癥狀?？偟膩?lái)說(shuō)，研究作者嘗試性地提出，大象的脂肪含量超過(guò)14%可以被認(rèn)為是肥胖，因?yàn)檫@個(gè)閾值與血液胰島素水平升高有關(guān)。

The researchers are keen to point, however, that more research is needed in order to verify this preliminary conclusion. Overall, though, they are pleased to report that on the whole, captive Asian elephants do not appear to be obese.

然而，研究人員熱衷于指出，需要更多的研究來(lái)驗(yàn)證這一初步結(jié)論。不過(guò)，總的來(lái)說(shuō)，他們很高興地報(bào)告說(shuō)：圈養(yǎng)的亞洲象似乎并不肥胖。