“Living Fossils” and Rhesus Monkeys

• Ancient animals and plants still found in present-day habitats have always fascinated biologists. For example, dragonflies have changed little over 300 million years, although the most ancient dragonflies were much larger than the ones we see today. A bite from a large dragonfly, such as the Common Blue Darner with its 4-inch wingspan, can barely break the skin of a human. However, if the dragonfly collector could be transported back 300 million years, an attempt to capture some of the ones that lived at that time could result in the collector losing a sizeable piece of flesh. Their wingspan could reach 29 inches.

The most significant “living fossil” is the horseshoe crab, which appears in the fossil record over 500 million years ago! These are true relics of the past. Their longevity may have something to do with the hard, turtle-like “shell” that protects the body and a kind of blood that clots when exposed to bacteria, sealing off an infection.

Another ancient survivor is likely responsible for providing our young planet with oxygen. Stromatolites, a kind of blue-green bacteria, form slimy mounds around ocean beaches today in much the same way they did 3.5 billion years ago. Long ago the planet had little atmospheric oxygen, but thanks to stromatolites and other primitive organisms that derived energy from photosynthesis (with oxygen as a byproduct), the planet acquired an atmosphere that could sustain higher forms of life. (Fortey, R., Horseshoe Crabs and Velvet Worms, The Story of the Animals and Plants That Time has Left Behind, Knopf, N.Y., 2012)

• Past research seems to show that short-lived animals tend to live longer when they are forced to live on a calorie-restricted diet, and a 2009 study at the University of Wisconsin – Madison found that restricted diet increased life span in Rhesus monkeys. A more recent study on Rhesus monkeys at the National Institute on Aging doesn’t support the UW Madison findings (the median life span for the Rhesus monkey is about 27 years). This study involved 121 monkeys divided between calorie-restricted and standard-diet groups. Now, 23 years into the study, more than half the monkeys have died and caloric restriction shows no survival advantage (i.e, there was no correlation between death and diet). Since some Rhesus monkeys can reach age 40, the final results will not be known for awhile. (Nature, Sept. 14, 2012; Science News, Oct. 16, 2012)

• A large study was just completed that supports a suspected link between non-steroidal anti-inflammatory drugs (NSAIDs) and heart attack risk. Such drugs include aspirin, ibuprophen, Celebrex, Naproxen, etc. Danish scientists reported on a study that followed first-time heart attack victims 30 years old or older for 12 years. Many of these received NSAIDs after the attack. Compared with people who did not receive NSAIDS, those who did were 63 percent more likely to have heart-related problems or die of another heart attack. (Circulation, Sept. 10, 2012)