【英语时差8,16】鱼的性格-上（在线收听）

Hot periods in July and August are called the dog days of summer because they do more than make a person sweat. People’s personalities change. They become tired and irritable. Tempers shorten. Many prefer lounging like a dog rather than working. It appears that humans aren’t the only animals that can have dog days in hot temperatures. Research has found that fish can have them too. Scientists have been investigating fish personality for quite some time. Some fish are shy and reserved, not venturing far from their protective habitat, and ducking for cover rapidly when threatened by new stimuli. Other fish are bolder, swimming out into the open more and acting aggressively to newly introduced objects and fish.