Scientists have long puzzled over how iguanas, a group of lizards mostly found in the Americas, came to inhabit the isolated Pacific islands of Fiji and Tonga. For years, the leading explanation has been that progenitors of the island species must have rafted there, riding across the Pacific on a mat of vegetation or floating debris. But new research in the January issue of The American Naturalist suggests that iguanas may have simply walked to Fiji and Tonga when the islands were still a part of an ancient southern supercontinent.

Education plays a key role in lifelong memory performance and risk for dementia, and it's well documented that those with a college degree possess a cognitive advantage over their less educated counterparts in middle and old age. But if you didn't attend college there's still a way to retain your memory, and it'll probably cost you a lot less than a degree.  A large national study published in the American Journal of Geriatric Psychiatry shows that people with less schooling can significantly compensate for poorer education by frequently engaging in mental exercises such as word games, puzzles, reading, and lectures.

Spending too many hours on the couch watching TV could cut your life short, according to a new study in Circulation. Australian researchers tracked the lifestyle habits of 8,800 adults and found that for every hour of television watched per day, the risk of dying earlier from cardiovascular disease increased by 18 percent. The team also found that each hour spent in front of the television daily was associated with an 11 percent increased risk of death from all causes and a 9 percent increased risk of cancer death.

Scorpion venom is composed of a complex cocktail of poisonous peptides that immobilize animal prey on the spot. Some of the toxins in this cocktail, however, are only harmful to insects, which has prompted researchers to harness them to create a safe and ecologically sound pesticide.

Scientists from Tel Aviv University's Department of Plant Sciences have isolated the genetic sequences for important neurotoxins in the scorpion venom and have also developed methods to produce and manipulate toxins to restrict their toxicity in certain insects or mammals. The findings appear in a study published in Molecular Biology and Evolution.

While genetics play a key role in children's initial reading skills, a new study of twins is the first to demonstrate that environment plays an important role in reading growth over time. The results, published in the Journal of Child Psychology and Psychiatry, give further evidence that children can make gains in reading during their early school years, above and beyond the important genetic factors that influence differences in reading.

The compounded effects of climate change and land development are taking a toll on California butterflies, says an analysis conducted by scientists from UC Davis and the University of Nevada, Reno. The new analysis, scheduled to be published online this week in the Proceedings of the National Academy of Sciences, gives insights into how a major and much-studied group of organisms is reacting to the Earth's warming climate.