Fonti delle illustrazioni

Con l’indicazione del numero della pagina e dell’ordine in cui le illustrazioni vi compaiono

American Museum of Natural History, New York, per gentile concessione dell’: 58.

Animals Animals/OSF, New York: 143; Animals Animals/E. R. Degginger, 144 (1).

British Museum, Londra, per gentile concessione del: 210 (1), 213 (1) (2), 219 (1); Riproduzione per gentile concessione degli Amministratori del British Museum: 210 (2), 213 (3).

© 1982 Ira Block/THE IMAGE BANK, New York: 12, 13.

Kentucky Department of Travel Development: 67.

Land Management, Bureau of, Washington: 69 (2).

Musei Nazionali Francesi, Museo del Louvre, Parigi: 212 (2).

National Aeronautics and Space Administration, Washington: 11, 128, 186 (2).

National Archives, Washington: 126 (1) (2), 224 (1), 225 (4).

National Park Service, Washington: 64 (1) Chukchi Imuruk.

National Zoological Park, Washington: 4 (1) e 69 (4) Brandy Clymire.

© Outdoor Pictures, Washington State: 54, 68.

Smithsonian Institution, Washington: 203 Foto n. 83-2259.

U.S. Fish & Wildlife, Washington: 3 (3) Dean Biggins, 4 (2) William Hartgroves, 63 (2) Dean Biggins (3) Glen Smart, 64 (2) Dean Biggins (3) Dan Pfitzer, 68 (4) William Hartgroves, 69 (1) (3) Dean Biggins.

U.S. Geological Survey, Washington: 225 (1).

Walters Art Gallery, Baltimora: 220.

World Health Organization: 224 (2) W. Cutting, 225 (2) Eric Schwab.