Elephants may be the largest land mammals on the planet, but new research has revealed that ordinary humans are actually more prosperous than these giant animals. Appearing in the journal Experimental Biology, the new study sheds light on the health of captive Asian elephants, suggesting that their low fertility rate may not be due to excess body fat. Sadly, many captive populations of Asian elephants are not self-sufficient, which is a cause for concern among biologists that obesity may affect animal fertility. However, while it is true that captive elephants usually carry more body fat than their wild parts, the effect of this extra weight on animal health never been properly investigated.
Therefore, a team of researchers set out to determine exactly how much of the body captive Asian elephants fat could label obese compared to their body weight. Explaining the difficulty in establishing such a determination, study author Daniella Chusy said in a statement, “Obesity in humans is not clearly defined, being an elephant alone.”
In their write-up, the authors expand on this issue by explaining, “Obesity is a social creation to describe people with high levels of adiposity, and was originally developed based on mortality data.”However, it is difficult to diagnose this type of disease in elephants, as “there is no data on the relationship between adolescence level and mortality in elephants.” Around 44 Asians from zoos across the United States and Canada were included in the study, including 35 females and 9 males. To meet the body fat of the animals, the researchers fed them pieces of bread that were soaked in heavy water, which contains an isotope of hydrogen called deuterium.
Zookeepers collected blood samples from elephants so that researchers could measure the level of deuterium circulation in the serum of each animal. The team was able to determine the fat level of each person by subtracting the amount of water in the blood of an elephant from the total weight of the body. On an average, male elephants carry about 8.5 percent body fat and females carry about 10 percent. In contrast, the average healthy person has between six and 31 percent fat, which means that most of us have a higher body fat ratio than captive Asian elephants.
More importantly, the results also revealed that the least fertile female elephants are the ones among the low-fat people who tend to have low fertility rates not due to obesity. Rather, it seems that female captive Asian elephants have the greatest risk of infertility due to being underweight. Furthermore, observations have shown that the elephants in the study tend to walk between 0.03 and 2.8 kilometers per hour. Previous studies have shown that wild Asian elephants typically walk between 0.01 and 1.15 kilometers per hour, indicating that the extra weight carried by captive elephants is not due to inactivity.
Finally, researchers reported that fattened elephants had higher levels of insulin, raising concerns that anyone could run the risk of symptoms such as diabetes. Overall, the authors of the study consistently suggested that elephants with more than 14 percent fat might considered obese, as this polarity was associated with improved blood insulin levels. Researchers, however, are interested in pointing out that more research needed to validate this preliminary conclusion. Overall, although they are satisfied to report that overall, captive Asian elephants do not appear to be obese.