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Abnormal coloration in bighorn sheep (Ovis canadensis).

Reports of abnormal coloration in wild vertebrates are encountered frequently in the literature. Abnormal white coloration manifests itself as albinism or leucism, and those terms are often used interchangeably, albeit erroneously (Curatolo 1979; McCardle 2012). Albinistic individuals are characterized by a complete lack of pigmentation in the skin and hair and have pink eyes; leucistic individuals (Fig. 1), however, are deficient in pigmentation and are white in color, but exhibit pigmented skin and eyes that are normally colored or blue (Abreu et al. 2013 for review). Leucism is a double-recessive trait (Cruickshank and Robinson 1997); hence, normally colored parents have the potential to produce leucistic offspring, but the genetics of albinism should not be confused with the genetics of leucism (Searle 1968).

Piebaldism involves a lack of pigmentation (Abreu et al. 2013) in some parts of the body, and piebald individuals are characterized by normally colored eyes (Fertl and Rosel 2002; Acevedo and Aguayo 2008). Miller (2005) noted that piebaldism has been referred to as partial albinism by some investigators, whereas others have not considered the differences between piebaldism and leucism; thus, the terminology associated with reports of abnormally pigmented animals frequently is confounded (Abreu et al. 2013). Melanistic individuals exhibit dark or even black pelage or appendages resulting from the excessive deposition of melanin, and this condition occurs less frequently than does albinism (Sage 1963).

Shackleton (1985) had reported an absence of records of abnormal coloration in bighorn sheep (Ovis canadensis) despite published reports of white-colored individuals (Jonez 1958; Hansen 1965a; Cooper 1974; O'Connor 1974; Wilson et al. 1975; McQuivey 1975, 1978; Jones 1980). Individuals exhibiting piebaldism also had been previously described (Hansen 1965a, 1965b), as had melanistic bighorn sheep (O'Connor 1974) and others whose coloration was described by Bunch and Nguyen (1982) as "melanistic black". Similar to Shackleton's (1985) report, McCardle (2012) did not include any records of white, albinistic, or leucistic bighorn sheep in a much more recent review.

My interest in this subject dates to 1976--when I learned that [greater than or equal to] 2 white-colored individuals had been seen in the Clark Mountain Range, San Bernardino County, California--and I have since then recorded all records of abnormally colored bighorn sheep that I became aware of. I also used several web-based bibliographic databases (EBSCOhost, JSTOR, Google Scholar, Harzing's Publish or Perish) and a web-based search engine (Google) to search for words or phrases (albinistic, leucistic, piebald, melanistic, pelage color, etc.) specific to abnormal coloration in bighorn sheep and reviewed results of those searches for references to abnormal coloration in that species. Additionally, I contacted numerous bighorn sheep biologists and other colleagues in the United States and Canada, as well as guides, outfitters, and hunters that had accumulated extended periods of time in the field, and queried each regarding observations of abnormally colored bighorn sheep. Finally, a simple questionnaire was distributed via e-mail to members and affiliates of the Northern Wild Sheep and Goat Council or the Desert Bighorn Council.


In western North America, bighorn sheep occupy suitable habitat in two Canadian provinces, 5 states in Mexico, and 15 of the contiguous United States. I carefully reviewed information from throughout the range of that species, including descriptions obtained from the literature or from electronic references, and the photographs, electronic images, or detailed descriptions provided by respondents. When information or the quality of an image was sufficiently detailed, I determined if individuals described either as 'white' or 'albino' were leucistic or albinistic. In addition, I reviewed the results of waterhole counts, aerial surveys, and other aerial events conducted from 1976 to 2009 by personnel from the California Department of Fish and Game (CDFG) or Bureau of Land Management (BLM) in the Nopah Range, Inyo County, California and the Kingston, Mesquite, and Clark Mountain ranges, San Bernardino County, California--areas from which leucistic bighorn sheep previously had been reported. I also reviewed results of aerial surveys of the Avawatz Mountains, San Bernardino County, an area of interest because the Southern Piute word avawatz implies "white sheep" (Werner 1951).

Contrary to information provided by Shackleton (1985) and McCardle (2012), observations of leucistic, melanistic, or piebald bighorn sheep have, for many years, been reported from throughout the range of the species (Table 1). In addition to the reports published prior to the reviews of Shackleton (1985) and McCardle (2012), abnormally colored bighorn sheep have now been described from [greater than or equal to] 30 geographic areas from British Columbia southward to Baja California Sur, and as far east as North Dakota. Further, white coloration has been reported among four of the five clades (O. c. canadensis, O. c. cremnobates, O. c. nelsoni, and O. c. mexicana) of bighorn sheep recognized by Buchalski et al. (2016). Reports of piebald or melanistic individuals were, however, much less common than reports of white-colored animals (Table 1). Although there likely are additional records of abnormal coloration in bighorn sheep not reported herein, this paper corrects the omissions of Shackleton (1985) and McCardle (2012) and, hopefully, will stimulate others to record additional observations of anomalous coloration in that iconic species.


I thank the many biologists, guides, hunters, and other interested parties that provided information on abnormally colored bighorn sheep they have observed in the field. I also thank K. Hurley (Wild Sheep Foundation) and A. Munig (Arizona Game and Fish Department) for distributing a brief questionnaire via the mailing lists of the Northern Wild Sheep and Goat Council and Desert Bighorn Council, respectively. I thank R. Weaver (CDFG) for making me aware of the presence of leucistic bighorn sheep in the Clark Mountain Range >40 years ago, and initiating my interest in this subject. This paper benefitted substantially from comments provided by three anonymous reviewers. Manuscript preparation and publication costs were supported by the Eastern Sierra Center for Applied Population Ecology and the Wildlife Investigations Laboratory of the California Department of Fish and Wildlife, respectively. This is Professional Paper 112 from the Eastern Sierra Center for Applied Population Ecology.

Literature Cited

Abreu, M.S.L., R.I. Machado, F.I. Barbieri, N.S. Freitas, and L.R. Oliveira. 2013. Anomalous colour in neotropical mammals: a review with new records for Didelphis sp. (Didelphidae, Didelphimorphia) and Arctocephalus australis (Otariidae, Carnivora). Braz. J. Biol. 73:185-194.

Acevedo, J. and M. Aguayo. 2008. Leucistic South American sea lion in Chile, with a review of anomalous color in otariids. Rev. Biol. Mar. Oceanog. 43:413-417.

Buchalski, M.R., B.N. Sacks, D.A. Gille, M.C.T. Penedo, H.B. Ernest, S.A. Morrison, and W.M. Boyce. 2016. Phylogeographic and population genetic structure of bighorn sheep (Ovis canadensis) in North American deserts. J. Mammal. 97:823-838.

Bunch, T.D. and T.C. Nguyen. 1982. Blood group comparisons between European mouflon sheep and North American desert bighorn sheep. J. Hered. 73:112-114.

Cooper, J. 1974. Nevada's desert bighorn sheep--1973 status report. T. Desert Bighorn Counc. 18:31-37.

Cruickshank, K.M. and T.J. Robinson. 1997. Inheritance of the white coat colour phenotype in African lions (Panthera leo). Pp 92-95 in Proceedings of a symposium on lions and leopards as game ranch animals (J. Van Heerden, ed.). Wildlife Group of the South African Veterinary Association, University of Pretoria.

Curatolo, J.A. 1979. A sighting of an albino caribou in Alaska and review of North American records. Arctic 32:374-375.

Ferris, L. 2013. Wyoming albino bighorn sheep: a trophy among trophies. Casper Star Tribune, 12 December 2013. Available from: -trophies/article_d6de6fb3-3255-5714-aca2-65ae1af7894d.html

Fertl, D. and P. Rosel. 2002. Albinism. Pp. 16-18 in Encyclopedia of marine mammals (W.F. Perrin, B. Wursig, and J.G.M. Thewissen, eds.) Academic Press.

Hansen, C.G. 1965a. White spotting in bighorn sheep from the Desert Game Range, Nevada. J. Mammal. 46:352-353.

Hansen, C.G. 1965b. Summary of distinctive bighorn sheep observed on the Desert Game Range, Nevada. T. Desert Bighorn Counc. 9:6-10.

Hansen, C.G. 1980. Physical characteristics. Pp. 52-63 in The desert bighorn (G. Monson and L. Sumner, eds.). University of Arizona Press.

Jones, F.L. 1980. Sign reading and field identification. Pp. 236-259 in The desert bighorn (G. Monson. and L. Sumner, eds.). University of Arizona Press.

Jonez, A. 1958. Hunting the desert bighorn sheep in Nevada. T. Desert Bighorn Counc. 2:1-5.

McCardle, H. 2012. Albinism in wild vertebrates. M.S. Thesis, Texas State University, San Marcos.

McQuivey, R.P. 1975. Bighorn research in Nevada. T. Desert Bighorn Counc., 19:15-18.

McQuivey, R.P. 1978. The desert bighorn sheep of Nevada. Nevada Dep. Wildl. Biol. Bull. 6:1-81.

Miller, J.D. 2005. All about albinism. Missouri Conservationist 66(6):4-7.

Morsette, A., Sr. 1996. Hidden man and the two holy men. Pp. 184-215 in Myths and traditions of the Arakara Indians (D.R. Parks, compiler). University of Nebraska Press.

NWRBC (Nevada Wildlife Record Book Committee). 1995. Nevada wildlife record book, Nevada Wildlife Record Book Committee, Reno, USA.

O'Connor, J. 1974. Sheep and sheep hunting. Winchester Press. 308 pp.

Sage, B.L. 1963. The incidence of albinism and melanism in British birds. Brit. Birds 56:409-416.

Searle, A.G. 1968. Comparative genetics of coat color in mammals. Logos Press, 308 pp.

Shackleton, D.M. 1985. Ovis canadensis. Mammalian Species 230:1-9.

Werner, L.T. 1951. We climbed Avawatz. Desert Magazine 14(10):20-24.

Wilson, L.O. and Members of the Desert and Mexican Bighorn Sheep Workshop Group. 1975. Report and recommendations of the desert and Mexican bighorn sheep workshop group. Pp. 110-143 in The wild sheep in modern North America (J.B. Trefethen, ed.). Winchester Press.

Vernon C. Bleich

Department of Natural Resources and Environmental Science, University of Nevada Reno, Reno, NV89557,

Caption: Fig. 1. Leucistic female and normal female bighorn sheep and leucistic male and normal male bighorn sheep in the Clark Mountain Range, San Bernardino County, California, 25 September 1998. Photograph by George C. Kerr, Society for the Conservation of Bighorn Sheep, used with permission.
Table 1. Locations of reported observations of unique color morphs of
bighorn sheep (Ovis canadensis) in North America. This compilation
almost certainly does not include every geographic area from which
color morphs have been reported, but it does establish the widespread
distribution of leucistic (L) or piebald (P) bighorn sheep, and those
described as 'albino' ('A') or simply as 'white' ('W') by the
reporting party. The sex(es) of the bighorn sheep seen appear
parenthetically; if not indicated, sex was not determined or
otherwise was not available.

Location          Trait (1) (Sex)   Source

Clark Mountain    'W'               R. Campbell, Society for the
Range, CA                           Conservation of Bighorn Sheep

                   'L '([male],     V. Bleich, R. Weaver;
                  [female])         California Department of Fish
                                    and Game (CDFG; multiple

                  L                 McQuivey (1978; leucism
                                    determined from McQuivey's
                                    [1975, 1978] published

Kingston Range,   'W' ([female])    J. Jaeger (University of
CA                                  Nevada, Las Vegas; in litt.)

Nopah Range, CA   L([male])         Yearling captured on 13
                                    November 1989 by R. Clark
                                    (CDFG) and W. Boyce (UC Davis)

Stateline         'L' ([male])      McQuivey (1978); J. Jaeger (in
Hills, CA and                       litt.) A. Pauli (CDFG; in
NV                                  litt.)

Cottonwood        'W'               J. Wehausen, White Mountain
Mountains, CA                       Research Station (personal
(2)                                 communication)

Spring             'W' ([male],     Hansen (1980); J. Rozich, U.S.
Mountains, NV     [female])         Forest Service (USFS); C.
                                    Stevenson, Nevada Division of
                                    Wildlife (NDOW); P. Cummings,
                                    NDOW; B. Jefferson, Fraternity
                                    of the Desert Bighorn; J.
                                    Zenz, bighorn sheep outfitter
                                    (each via personal
                                    communication); NWRBC (1995)

                  'A' ([female])    Cooper (1974)

                  'A', 'W'          McQuivey (1975)

                   'L '([male],     McQuivey (1978) (leucism
                  [female])         determined from McQuivey's
                                    published descriptions)

                  'L' ([male]),     V. Clark (personal
                                    communication; leucism
                                    determined from photograph)

                  L([male],         http://wwwbirdandhike.
                  [female])         com/Wildlife/
                                    white.htm (leucism determined
                                    from photograph)

                                    donniebarnett. html (leucism
                                    determined from photograph)

                                    355935 (leucism determined from

                  L([male])         wwwaroundthebendfriends2.
                                    (leucism determined from

Near Las Vegas,   'A' ([male])      O'Connor (1974; sex was
NV                                  inferred from O'Connor's

Muddy             'W'               McQuivey (1978)
Mountains, NV

El Dorado         'W'               McQuivey (1978)
Mountains, NV

Pintwater          'P ', 'W '([male]Hansen (1965a)
Range, NV         [female])

                  'W'               E. Pribyl, Fraternity of the
                                    Desert Bighorn (personal

Highland Range,   'W'               E. Pribyl (personal communication)

Hiko Range, NV    'W' ([male])      J. Zenz; C. Stevenson; P.
                                    Cummings; E. Pribyl (each via
                                    personal communication)

Ruby Mountains,   L([male])         L. Spradlin (personal
NV                                  communication; leucism
                                    determined from photograph)

Sierra Ancha,      'L' ([male],     D. Darveau, Arizona Game and
AZ                [female])         Fish Department (AZGFD;
                                    personal communication)

Near Roosevelt    L([male],
Lake, AZ          [female])         topic/18168-some-white-bighorn-
                                    sheep/ (probably leucistic
                                    as determined from photographs)

Silver Bell       'P' ([male])      D. Aubuchon, AZGFD; B. Brochu,
Mountains, AZ                       AZGFD (each via personal

Little            L' ([female])     M. Brown (AZGFD, personal
Harquahala                          communication; leucism
Mtns, AZ                            determined from description)

Grand Canyon,     L ([female])
AZ                                  singleitem/collection/cpa/id/
                                    3686/rec/11 (leucism
                                    determined from photograph)

                  'W' ([female])    M. Jorgensen, California
                                    Department of Parks and
                                    Recreation (personal

                  L([male])         M. Jorgensen (personal
                                    communication; leucism
                                    determined from description of

Wind River        L([male])         Ferris (2013; leucism
Range, WY                           determined from photograph)

                  'W' ([male])      K. Hurley, Wyoming Game and
                                    Fish Department (personal

Thoroughfare      'W'               J. Stradley and K. Alt,
Canyon, WY                          Montana Department of Fish,
                                    Wildlife and Parks (personal

Skaha Lake, BC,   L ([female])      A. Reid, British Columbia
Canada                              Ministry of Forests, Lands and
                                    Natural Resource Operations
                                    (personal communication;
                                    leucism determined from

                  L ([female])
                                    determined from photograph)

Badlands, ND      'W'               Morsette (1996)

T. Roosevelt      'L'               B. Wiedmann, North Dakota Game
National Park,                      and Fish Department (personal
ND                                  communication)


Not disclosed     'W'               Jones (1980)

Bitterroot        L ([female])      K. Hurley (personal
Range (Unit                         communication; leucism
20A), ID                            determined from photograph)

Sheep Mountain    'W' ([male])      K. Hurley (personal communication)
(Unit 36A), ID

                  'W' ([female])    J. Walters and M. Johnson,
                                    USFS (personal communication)

Lemhi Range, ID   'L'               J. Walters and M. Johnson,
                                    USFS (personal communication)

                  'L' ([female])    B. Crompton, Utah Division of
West of Abajo                       Wildlife Resources (UDWR;
Mountains, UT                       personal communication)

Bookcliff         'P' ([male])      R. Thacker, UDWR (personal
Mountains, UT                       communication)

San Juan River    'P' ([male])      G. Wallace, UDWR (personal
Canyon, UT                          communication)

Antelope          'L' ([male])      R. Robinson, UDWR (personal
Island, UT (3)                      communication)

                                    ?type=3&theater (leucism
                                    determined from photograph)

Sierra de San     'W'               Wilson et al. (1975)
Pedro Martir,

(1) Single quotation mark around a trait indicates it was described
by the original observer(s); an absence of quotes indicates the
designated trait was assigned by V. Bleich from information available
from, or provided by, the source.

(2) Riverside County.

(3) UDWR personnel translocated this individual, a male lamb, from
Antelope Island to the Canyon Mountains, Utah, in January of 2016.
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Author:Bleich, Vernon C.
Publication:Bulletin (Southern California Academy of Sciences)
Article Type:Report
Geographic Code:1USA
Date:Apr 1, 2017
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