How Do Gorillas Get Heart Disease? And More Questions From Our Readers

Q: I’ve heard that gorillas often suffer from heart disease. What are the main risk factors?

—William Mosteller | Fairfax, Virginia

Muscular, vegetarian gorillas may seem less likely than humans to have cardiovascular disease, but it’s the leading cause of death for captive apes, killing more than 40 percent of male gorillas in North American zoos. Based on studies of gut bacteria and other factors, researchers at zoos are rethinking the types and quantities of food given to great apes, including shifting from processed nutrient biscuits to the kinds of stems, shoots and fruits wild gorillas eat. To avoid giving the gorillas anesthesia, which can place an extra burden on their hearts, Becky Malinsky, curator of primates at the Smithsonian’s National Zoo, says her team has trained its gorillas to cooperate with heart ultrasounds and other data-gathering procedures. The veterinarians send the information they collect to the Great Ape Heart Project, a collaborative program based at Zoo Atlanta.

Q: Why did ancient Egyptians remove a corpse’s brain and other organs before mummifying it?

—Jeaneth Larsen | Mitchell, South Dakota

To keep the corpse nice for the next life. Egyptians believed the body would travel to the afterlife, says Alexander Nagel, a research associate at the National Museum of Natural History. But the only organ they deemed necessary for this journey was the heart, which they saw as the center of a person’s soul and which they often left intact. After removing the other organs, Egyptians rubbed the corpse with a salt mixture to dry it out, another way to slow decay. They administered spices, herbs, perfumes and oils to keep the body supple and combat foul odors. When it came to wrapping, more important individuals got more complex wraps. Amulets placed in the wrappings warded off evil on the journey to the beyond.

Q: Are burping and acid reflux different for astronauts in space, since there’s no right side up?

—Del Langer | Sarasota, Florida

Yes. In microgravity, air stays intermixed with food particles, says Jennifer Levasseur, curator at the National Air and Space Museum. So burping in space is more likely to result in vomiting. Astronaut Jim Newman developed his own technique to reduce the likelihood of vomiting: He’d push off a wall to create a force that separated the food from the gases in his stomach, much the way gravity does.

Q: Do saltwater fish have a higher sodium content than freshwater fish?

—David Majercik | Westhampton, Massachusetts

Yes, but they’re not as salty as the oceans themselves. The gills of saltwater fish help pump out excess sodium, as well as other minerals like potassium and chloride. Studies suggest this process is controlled by different hormones. In freshwater fish, the process works in reverse: Their gills help pump salt in instead of out. Striped bass are particularly adept at maintaining an osmotic balance in both environments, says Matt Ogburn, senior scientist at the Smithsonian Environmental Research Center. Although the bass hatch in freshwater, they migrate to saltwater before their first winter, and return to freshwater to spawn.

It’s your turn to Ask Smithsonian.

Natalie Hamilton | READ MORE

Natalie Hamilton is an editorial assistant for Smithsonian magazine.