Scientists Study Monkey Faces and Cat Bellies; Another Intermediate Black Hole in the Milky Way

This isn’t a repeat of last week’s roundup; another group of astronomers has found a second intermediate-mass black hole in the Milky Way, and I can’t help but point it out. They’re cool! They may have formed in the early universe, they comprise the seeds of supermassive black holes, and they may have formed by the accretion of multiple stars into a cluster rather than by stellar collapse.

If there’s a third one next week, I’ll be irresistibly compelled to tell you about it. If there’s a fourth one after that, I promise to put it in a footnote. Other than that, scientists have observed monkeys making faces at each other, and a group of researchers have studied cat poop, a plentiful resource, to draw conclusions about human metabolism.

Medium-sized thing, scientists say

Last week, we reported the first discovery of an intermediate-sized black hole right here in the Milky Way galaxy, and this week, astronomers at the University of Cologne reported a second one in the immediate vicinity of Sagittarius A*, the supermassive black hole at the center of the galaxy. The researchers were studying a star cluster called IRS 13.

Located 0.1 light-years from the galaxy’s core (which is another way of saying “inside” the galaxy’s core), the cluster exhibits such a surprisingly orderly pattern of motion among its stars and such an unexpected density that researchers can only draw two conclusions: either IRS 13 is interacting with Sagittarius A* in some way, or a gravitational object at the center of the cluster is influencing the motion of its stars and keeping the cluster compact. Multiwavelength observations of the cluster via the Very Large Telescope, ALMA, and the Chandra X-ray telescope support the existence of an intermediate-class black hole in IRS 13.

Cats per kilo

Domestic cats are a lot like people: They live in climate-controlled indoor environments, lounge on furniture, and often have easy access to prepared food. So scientists have come to the conclusion that they make a great disease model for human ailments. In a new study, researchers at Ohio State University analyzed feline gut microbes to study the origins of obesity.

Jenessa Winston, an assistant professor of veterinary clinical sciences at Ohio State University, says, “Animals share our beds. They share our ice cream. There are all these things that people do with their pets that highlight that they are a natural disease model with similar environmental exposures to humans.”

The researchers fed seven obese cats a four-phase diet: for the first two weeks, the cats ate commercial cat food via open feeding; for one week, they were freely fed a weight-loss formula; then they were switched for 11 weeks to a calorie-restricted weight-loss diet; and finally, they returned to their original maintenance diet. By analyzing fecal samples, the researchers were able to track changes in metabolites produced by the cats’ gut bacteria, which are associated with metabolic factors throughout the body, including hormonal signals related to inflammation and insulin resistance.

An abundance of a short-chain fatty acid, propionic acid, increased during weight loss. “When cats are on the special diet formulated for weight loss, propionic acid goes up and stays high, and then goes back down when they are put back on the maintenance diet. So it’s really a dietary change,” says Winston.

Study finds expressive monkeys are popular

Social animals tend to have a lot of facial musculature. For example, scientists theorize that the development of complex orbital muscles in dogs during domestication helped them communicate better with humans (who have a very high level of facial muscle complexity, the Schwarzeneggers of facial muscle mass, symmetry, and conditioning). Facial expressions convey information and context, and are an important channel of communication.

Now, researchers at Nottingham Trent University studying rhesus monkeys report that monkeys with high facial expressiveness have stronger social connections and are more successful socially. Their study included nine social groups of monkeys with similar compositions: one adult male, several adult females, and infants. They developed a coding system to track 17 facial muscle movements, focusing on the dominant males in each group. They also quantified the social networks of all 66 monkeys in the study, including time spent between specific pairs and grooming interactions between group members.

Males that displayed high facial expression diversity had stronger social bonds and were likely to be central nodes in their social networks. “Individuals with facial expression may be better equipped to build and maintain strong social connections, potentially leading to the range of benefits associated with group cohesion, such as increased access to resources, mating opportunities and protection from threats,” says lead author Dr Jamie Whitehouse.

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