Dementia affects one-third of all people older than 65 years in the United States. The most common cause of dementia is Alzheimer’s disease, a progressive, irreversible brain disease that results in impaired cognitive functioning and other behavioral changes. Humans are considered uniquely susceptible to Alzheimer’s disease, potentially due to genetic differences, changes in brain structure and function during evolution, and an…
Poor sleep is often regarded as a modern affliction linked to our sedentary lifestyles, electric lighting and smartphones on the bedside table. However, new research suggests that fitful sleep could be an ancient survival mechanism designed to guard against nocturnal threats. The study, which tracked the sleep patterns of a modern-day hunter-gatherer tribe in northern Tanzania, found that frequent night-time…
No bells tolled when the last Catarina pupfish on Earth died. Newspapers didn’t carry the story when the Christmas Island pipistrelle vanished forever. Two vertebrate species go extinct every year on average, but few people notice, perhaps because the rate seems relatively slow – not a clear and present threat to the natural systems we depend on. This view overlooks…
First Big Efforts to Sequence Ancient African DNA Reveal How Early Humans Swept Across the Continent
The study of ancient human DNA has not been an equal opportunity endeavor. Early Europeans and Asians have had portions of their genomes sequenced by the hundreds over the past decade, rewriting Eurasian history in the process. But because genetic material decays rapidly in warm, moist climates, scientists had sequenced the DNA of just one ancient African. Until now. This week,…
After observing the mating habits of chacma baboons living in the wild over a four-year period, researchers have found that males of the species often use long-term sexual intimidation to control their mates. The findings suggest that this mating strategy has a long history in primates, including humans, and may be widespread across social mammals — especially when males of…
The asteroid that hit Earth 66 million years ago spelled disaster for the dinosaurs. But scientists say they’ve found one silver lining to the mass extinction — turns out, it was really good for frogs. The resilient animals date back some 200 million years. And in the aftermath of the extinction event, they survived and thrived, taking advantage of an…