But they have always been the creatures investigated most by humans. Because we ourselves are large terrestrial vertebrates, mammals have the closest "blood ties" with man, while the birds, with their gift of flight, fire man's rich imagination, and are pleasing in their appearance.
由於人類自身屬於大型陸生脊椎動物，哺乳動物與人類「血緣關係」最密切；會飛行的鳥類，給人豐富的想像，外型又討好，常成為生態研究的優先選擇。