Biological Exuberance: Animal Homosexuality and Natural Diversity

Mallard Duck here, here, and here: Photos by Friedrich Schutz. Reprinted from Schutz (1965: Fig. 3, p. 443; Figs. 4—5, p. 446) with the permission of Springer-Verlag. © 1965 by Springer-Verlag.

Orang-utan here and here: Photos by H. D. Rijksen. Reprinted from Rijksen (1978: Fig. 128b, p. 263; Fig. 129a, p. 264) with the permission of H. D. Rijksen. © 1978 by H. D. Rijksen.

Bonnet Macaque: Photo by Yukimaru Sugiyama. Reprinted from Sugiyama (1971: Fig. 6, p. 260) with the permission of Japan Monkey Centre and Yukimaru Sugiyama. © 1971 by Primates/Japan Monkey Centre.

Mute Swan: Photo by J. P. Ritchie. Reprinted from Ritchie (1926: p. 95) with the permission of Oliver & Boyd/Addison Wesley Longman Ltd. © 1926 by Oliver & Boyd/Addison Wesley Longman Ltd.

Melolonthine Scarab Beetle: Drawing by A. L. Clement. Reprinted from Gadeau de Kerville (1896: p. 85).

Gray Whale here and here: Photos by James Darling. Printed from Darling (1978: Fig. 13A-B, p. 54a) with the permission of James Darling. © 1978 by James D. Darling.

Greylag Goose: Photo by Angelika Tipler-Schlager. Reprinted from Lorenz (1991: Fig. 95, p. 227) with the permission of Angelika Tipler. © 1991 by Angelika Tipler.

Gray Seal: Reprinted from Backhouse and Hewer (1957: Plate 1, p. 450) with the permission of Cambridge University Press. © 1957 by the Zoological Society of London.

Red Fox: Photos by David W. Macdonald. Reprinted from Macdonald (1980: Plate 2a-b, p. 137) with the permission of David W. Macdonald. © 1980 by David W. Macdonald.

Takhi/Przewalski’s Horse: Photo by Judy Rosenthal and Amy Kasuda. Printed with the permission of Katherine A. Houpt. © 1999 by Katherine A. Houpt.

Black-winged Stilt here and here: Photos by Tamaki Kitagawa. Reprinted from Kitagawa (1988: Fig. 2a-b, p. 64) with the permission of Tamaki Kitagawa. © 1988 by Tamaki Kitagawa.

Red-backed Shrike here and here: Photos by Eric Ashby. Reprinted from Ashby (1958: p. 272) with the permission of The Countryman/Link House Magazines. © 1958 by The Countryman/Link House Magazines and Eric Ashby.

White-tailed Deer: Photo by Leonard Lee Rue III. Reprinted from Marchinton and Hirth (1984: p. 150) with the permission of Leonard Rue Enterprises. © 1984 by Leonard Lee Rue III and Len Rue Jr.

Common Chimpanzee: Photo by Toshisada Nishida. Reprinted from Nishida (1970: Fig. 6, p. 81) with the permission of Yukimaru Sugiyama/Japan Monkey Centre. © 1970 by Primates/Japan Monkey Centre.

American Bison: Photo by S. Oberhansley. Courtesy Record Group 79, National Archives and Records Administration, Yellowstone National Park.

Inuit shaman’s cloak: Photo by P. Hollenbeak. Image #2A13527, courtesy Department of Library Services, American Museum of Natural History.

Eastern Gray Kangaroo: Photo by Jenny Norman and Ron Oldfield. Printed with the permission of D. W. Cooper. © 1999 by D. W. Cooper.

Bonobo here and here: Photos by Takayoshi Kano. Reprinted from Kano (1992; pp. 178, 179, 192) with the permission of Stanford University Press and Takayoshi Kano. © 1992 by the Board of Trustees of the Leland Stanford Junior University.

Bonobo: Photo by Frans de Waal. Reprinted from de Waal (1987: Fig. 6, p. 325) with the permission of Frans de Waal. © 1987 by Frans de Waal.

Gorilla: Photos by Juichi Yamagiwa. Reprinted from Yamagiwa (1987: Figs. 5a—b, p. 12) with the permission of Yukimaru Sugiyama/Japan Monkey Centre and Juichi Yamagiwa. © 1987 by Primates/Japan Monkey Centre.

Hanuman Langur: Photo by Volker Sommer. Reprinted from Srivastava et al. (1991: Fig. 1, p. 495) with the permission of Plenum Publishing Corporation and Volker Sommer. © 1991 by Plenum Publishing Corporation.

Rhesus Macaque: Reprinted from Akers and Conaway (1979: Fig, 7, p. 73) with the permission of Plenum Publishing Corporation. © 1979 by Plenum Publishing Corporation.

Bonnet Macaque: Photo by Paul Simonds. Reprinted from Simonds (1965: Fig. 6-5, p. 183) with the permission of Holt, Rinehart, and Winston and Paul Simonds. © 1965 by Holt, Rinehart, and Winston and renewed 1993 by Irven DeVore.

Savanna Baboon: Photo by Timothy W. Ransom. Reprinted from Ransom (1981: Plate 5-A[3], p. 84) with the permission of Associated University Presses. © 1981 by Associated University Presses, Inc.

Savanna Baboon: Photo by K. R. L. Hall. Reprinted from Hall (1962: Plate 1, Fig. 2, p. 326) with the permission of Cambridge University Press. © 1962 by the Zoological Society of London.

Squirrel Monkey: Photo by Frank DuMond. Reprinted from DuMond (1968: Fig. 12, p. 125) with the permission of Academic Press, Inc. © 1968 by Academic Press, Inc.

Boto: Photo by James N. Layne. Reprinted from Layne and Caldwell (1964: Plate 1, Fig. 2, p. 108) with the permission of James N. Layne. © 1964 by James N. Layne.