Zoo Monkeys are Becoming More Human as Seen in Their Guts

Does captivity make monkeys more human-like? While there is not much evidence to prove this, findings from a recent research has given light to the speculations by showing that the microbiomes in monkeys' guts become more human-like if they are kept in captivity.

Researchers from the University of Missesota collected DNA from the feces of both captive and wild monkeys, the endangered red-shanked douc and the confined howler monkey. After DNA sequencing, they realized that gut microbes of the two were much different.

The monkeys in captivity have less diverse microbes in their gut and also lack native microbes. Rather, these are replaced with those that are commonly found in human gut.

For confirmation, they also did the same experiment with eight other species in a different zoo. Their experiments yielded the same results.

"We don't know for certain that these new modern human microbes are bad, but on the other hand many studies are now showing that we evolved together with our resident microbes," Dan Knights, a computer science and engineering professor at Minnesota, explained in a news release provided to Phys.Org.

"If that is the case, then it is likely not beneficial to swap them out for a totally different set."

Aside from the diversity of microbes, the researchers also found out that captive monkeys engage in less fiber and plant diet. United Press International notes that this kind of diet might be the reason why there is change in captive monkeys' gut microbiome.

The researchers suggested that captivity may be part of the reason why biodiversity in their species decrease over time.

"Solutions might include increase the diversity of plant fiber in their food to mimic wild diets more closely, or even to do fecal transplants from wild animals to captive individuals under some kind of gastrointestinal distress," Knights told The Atlantic in a separate interview.

The paper was published in the journal Proceedings of the National Academy of Sciences.