A cat s tail says a lot about what he's thinking. • Want to read a cat’s mood? Watch the tail. A tail held straight up indicates a cat who’s relaxed or in a mood to greet company. When the tail is moving side to side, however, it’s not a friendly sign: Wagging tails in cats indicate the increased agitation of a cat who is getting ready to pounce.

• The domestic dog originated 16,000 years ago in Asia, south of the Yangtze River in China, according to a study in the scientific journal Molecular Biology and Evolution. The domestication of the dog coincides with the transition of humans from huntergatherers to farmers. The ancestors of dogs were a large number of animals, at least several hundred wolves, but all came from a single geographical area. The original dogs in what’s now Europe were used as herders and guard dogs, while the original dogs in China seemed to have been used for human consumption.

• Mice are aiding NASA. A study by NASA’s Jet Propulsion Laboratory has been finding ways to study the effects of weightlessness on astronauts by testing a magnetic field on mice. The study could aid in preventing bone deterioration for astronauts on long missions.

• Wild horses show less variety in coat colors and markings than domesticated horses. Wild horses need coats that provide camouflage, encourage mating and have more tolerance to certain pathogens. As domestication progressed, human preference chose certain colors and patterns, leading to the diversity we see in domestic horses today.

— Dr. Marty Becker and Mikkel Becker Shannon