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Picture of a black jaguar reputedly hunted in Belize

BLACK JAGUARS IN BELIZE?:
A SURVEY OF MELANISM
IN THE JAGUAR, Panthera onca

Black Jaguar at the Belize Zoo (imported)  in the Belize Zoo. Notice the spots on the hindleg of the animal

 

 

John R. Meyer, Ph.D.

September 1994

During my travels throughout Belize, I have occasionally encountered reports and rumors regarding the occurrence of the black, or melanistic, phase of the jaguar, Panthera onca, in Belize. During 12 years spent as a staff member at the Jacksonville Zoo in Jacksonville, Florida, I had the opportunity to be involved with a breeding program that produced both black and spotted phases of the jaguar. As an outgrowth of my interest in elucidating the genetics of melanism in this cat, I undertook a survey of the occurrence of this phenomenon in the wild, a project that revealed some interesting facets of the distribution and occurrence of melanism in wild jaguars.

Jaguars have been maintained in captivity for several centuries, going back to at least the early 1500's, when they were reported in the emperor Montezuma's collection in what is now Mexico City (Diaz, 1956). From that time until the middle of the present century, captive breeding was sporadic, as it was a relatively easy matter to acquire replacement animals from the wild. By the early 1970's, when serious conservation efforts were initiated with the Endangered Species Act (ESA) and the Convention on International Trade in Endangered Species (CITES), the reproduction of jaguars in zoos was well-established and the captive population self-sustaining.

There occurs in jaguars, as well as in leopards (Panthera pardus), a melanistic phase which has been much sought by zoos for exhibition purposes. This color phase was relatively difficult to acquire until the 1970's, by which time a few zoos, among them the Jacksonville Zoo, had begun to breed them regularly. Until this time, it had been assumed that the black phase of the jaguar, as is the case for the leopard, was the result of a recessive genetic trait. By the late 1970's, it had been demonstrated conclusively that melanism in jaguars is a result of a dominant allele (Deutsch, 1975; Dittrich, 1979); in spite of this documentation in the literature, the phenomenon was not widely recognized throughout the research community until the late 1980's. Mondolfi and Hoogesteijn (1982) considered melanism in jaguars to represent a recessive condition, and several field biologists (Robin Best, in litt.; Russell Mittermeier, in litt.; Alan Rabinowitz, in litt.) expressed surprise upon learning from the author that the opposite was true. One probable reason for this misconception, in addition to the situation with leopards, is the fact that the melanistic phase does not occur throughout a large portion of the jaguar's range, and where it does occur it is usually with a lower frequency than the spotted phase (Nowak, 1991). Most of the large cats have extensive geographical distributions, and the jaguar is no exception. Its range has shrunk somewhat in the past century due to man's persecution, but historically the jaguar was found from the southwestern U.S. through Mexico and Central America to South America, where it was widespread east of the Andes and south as far as the Argentine pampas (Guiggisberg, 1975; Nowak, 1991). Since jaguars in general are secretive, reliable reports of melanistic individuals are difficult to acquire, particularly from the literature. Without doubt, Brazil has the largest population of black jaguars, not surprising since this country contains the largest remaining wilderness area in the jaguar's range. Melanistic individuals have been reported from the following states of Brazil: Amazonas by Bates (1892) and Almeida (1976); Para by Smith (1976), E. Im Thurn, 1883 (cited in Perry, 1970), Shoumatoff (1978), Almeida (1976), and Sick (1961); Rio Branco by Shoumatoff (1978); Mato Grosso by Roosevelt (1926) and Wavrin (1936); Minas Gerais by L.A. Deutsch (in litt.), Russell Mittermeier (pers. comm.), and Almeida (1976); Goias by L.A. Deutsch (in litt.).

Elsewhere in South America, black jaguars have been reported from Venezuela (Humboldt, 1853; Mondolfi and Hoojesteijn, 1982), Guyana, R. Schomburgk, 1922 (cited in Perry, 1970), Ecuador (Wavrin, 1936), Peru (Wavrin, 1936; Poeppig, 1835; J. von Tschudi, 1847 (cited in Perry, 1970); John Terborgh, in litt.), and Paraguay (Rengger, 1830). The Jacksonville Zoo had a wild caught male that was shipped from Leticia, Colombia, but could have originated from nearby Brazil or Peru, as well as Colombia. Upon its death, this male was deposited in the collection of the Florida Museum of Natural History. Although no literature records have been encountered, it is likely that melanistic individuals occur in the South American countries of Suriname, French Guiana, and Bolivia, particularly in those areas in or adjoining the Amazon basin.

Outside of South America, the only published report of melanism encountered was that of Perry (1970), who stated that A. Verrill found black jaguars greatly feared by the Indians in Costa Rica. Christopher Vaughan reported (in litt.) that there have been several reported sightings in Costa Rica, but there are no specimens to substantiate these claims. Following his two year study of jaguars in Belize, Rabinowitz (1986) stated that there were probably no black jaguars in that country, although Sharon Matola of the Belize Zoo indicated to the author that she has seen what appeared to be a melanistic jaguar in Belize. In spite of persistent reports of black jaguar sightings (Jan Meerman, pers. comm.), my own investigations and experience in Belize lead me to agree with Rabinowitz, particularly given the lack of documented records for the nearby countries of Mexico, Guatemala, and Honduras. In the absence of any other indication of melanism in Central America or Mexico (Leopold, 1959), a region relatively well-explored biologically, it seems reasonable to state that black jaguars do not occur outside of South America, and more specifically, not beyond the northern periphery of the Amazon basin in Colombia. Nevertheless, it is not impossible that isolated populations might contain the allele for melanism, and certainly Belize, with its relatively large jaguar population, warrants further examination.

No scientific study has yet been undertaken in any part of the black jaguar's range to determine its abundance with respect to the spotted phase. Smith (1976) stated that the unspotted cats (including melanistic jaguars) have little commercial value in the illegal Amazon skin trade, so a survey of that activity would probably not reflect the relative abundance. A survey on the status of the jaguar (Swank and Teer, 1987) contains no information on the spotted versus the melanistic phase. The anecdotal evidence indicates that there is a wide range of incidence of melanism in jaguars, ranging from uncommon to frequent, and there appears to be a possible geographic trend in this incidence. The uneven incidence of the melanistic phase of the jaguar in the wild raises some interesting questions, not the least of which is how it came to its present apparent pattern of distribution. Three categories of factors suggest themselves as possible elements in the development of the observed situation. It may prove to be that only one of these factors is responsible, or a combination of several factors may be the directing force.

Genetic factors may be operating to limit the frequency of the black morph in the wild, although at present there is no evidence suggesting how this may operate (Rabinowitz, 1986). Robinson (1970), in a study of melanism in leopards, discovered what appeared to be a reduction in litter size in matings involving two black individuals, but in this case the melanism is a recessive trait. The data available from captive breeding of jaguars (Dittrich, 1979; Deutsch, 1981; pers. observ.) give no indication that there is any difference in litter size in pairings involving two blacks, two spotteds, or black with spotted crosses. Robinson (1970) further noted that in certain areas, particularly the forests of southeast Asia, the black phase of the leopard may outnumber the spotted phase, and he suggested that if the disadvantage associated with reduced litter size in black leopards operates in the wild, it may be a factor in the maintenance of the spotted/black dimorphism. The failure of the black phase to completely displace the spotted could depend on this aspect. An analogous system, as yet unsuspected, may be operating in the case of the jaguar, responsible for the maintenance of a dimorphic color pattern. It is interesting to speculate that there could be some selective disadvantage (even lethal) in the homozygous dominant condition in black jaguars, but the data on matings of two blacks are too limited to show evidence of reduced viability. It does appear from what evidence is available involving crosses of black with spotted jaguars (Dittrich, 1979; pers. observ.) that most, if not all, of the black parents were heterozygous for the color alleles.

Another set of factors that may have determined the present distribution and abundance of black jaguars may be termed historical, referring in this case to the geologic and climatic history of the American continents. Simpson (1980) stated that "the jaguar or its immediate ancestor evolved in Asia and spread through both the Americas without further radiation". He further indicated that jaguars are known from fossils in South America from the middle Pleistocene (Ensenadan) onward. Fossil evidence shows that the species occurred in Florida as recently as 7000 to 8000 years ago (Martin and Webb, 1974), and Guggisberg (1975) felt that it may have been encountered as far north and east as southern Louisiana in recent times. Unfortunately, there is no way at present to determine from the fossil material what the color pattern of these early jaguars was, so an analysis of the effects of past climatic and geologic change has to be based on indirect evidence.

In recent years, an increasing body of knowledge has become available on the geologic and climatic history of Central and South America. For the jaguar, the Pleistocene history is of greatest potential significance, and some of what is now known or hypothesized concerning this time period is of interest. Several authors (Haffer, 1979; Duellman, 1979; Simpson, 1979; Lynch, 1979; Dixon, 1979; Dixon and Rivero Blanco, 1979) have summarized much of the data concerning the Pleistocene biogeography of South America, and the evidence presented indicates that there are several historical possibilities that could account for the present apparent distribution and frequency of the black jaguar. Unfortunately, not enough hard evidence is presently available regarding the incidence of the melanistic phase to make it worth speculating on the possible effects of Pleistocene climatic fluctuation. However, it does seem that if the pattern of distribution and frequency as it presently appears should prove to be real, the past climate and its resultant ecologic changes will probably provide the best hypothesis to explain the phenomenon.

The final set of factors that may have some bearing on the determination of the present distribution of melanistic jaguars may be termed ecologic. This can include all manner of biological relationships, ranging from prey species to habitat types, and almost certainly some have had roles in influencing the evolution of the jaguar.

Throughout its entire range, the jaguar is known to inhabit a wide variety of habitat types, and has been recorded at elevations ranging from sea level to almost 3000 meters (Guggisberg, 1975; Perry, 1970). Most observers and researchers seem to feel, however, that the optimum habitat for jaguars is the wetter lowland areas, with vegetation ranging from mixed savanna to rainforest (Mondolfi and Hoogesteijn, 1982; Guggisberg, 1975; Thornbeck and Jenkins, 1982). In the long term evolutionary history of the jaguar, it may have been this optimum habitat and its fluctuating history that has had the greatest influence upon the development of the present distribution pattern. Of the black phase, very little is known regarding optimum environmental conditions, but the impression gained from the distribution records is that it is primarily an animal of rainforest areas. Certainly a tempting hypothesis is that the melanistic form is difficult for prey to see in the darkened rainforest, and this may eventually prove to be the case. It should be pointed out, however, that within the range of the jaguar there are, or historically were, areas of fairly extensive rainforest within which black jaguars do not occur. It is likely that the ultimate explanation for the uneven distribution of the black morph will involve several factors, such as fluctuating climate and rainforest distribution, which may have resulted in its absence in Central America and Mexico.

Until field studies are undertaken of a population with a high incidence of melanistic individuals, it is futile to speculate further on the relative importance of various factors, be they genetic, ecologic, or historic. There is also a great need for additional field studies of populations throughout the range to develop a better understanding of the variation in the ecology of this widespread species, especially given the ever-shrinking range of the species.

Belize, with its relatively large population of jaguars and the prospect for their continuing existence, presents an ideal situation for more detailed field studies, and
data gathered in these studies would be of great comparative value with data gathered from populations containing melanistic individuals in South America. It will also be of great value for Belizean biologists, naturalists, and protected area personnel to report all jaguar sightings to a centralized data center so that reliable information on jaguar distribution, frequency, and pattern can be evaluated.

Mounted Black Jaguar form Belize Latest report: This black jaguar was reportedly killed in Belize (then British Honduras) in the early 70's. The people who helped with the dogs had no idea that the cat was in the area and were, reportedly, terrified that the spirit of the animal would hunt them. The outfitter seemed to believe that black cats were rare because the mother cats would kill the "different" kit. It is still on the mount today

Literature Cited

Almeida, A. 1976. Jaguar hunting in the Mato Grosso. Stanwill Press, London.

Bates, H.W. 1892. A naturalist on the River Amazon. London.

Deutsch, L.A. 1975. Contribuicao para o conhecimento do Panthera onca (Linne) - onca pintada (Mammalia-Carnivora). Cruzamento de exemplares pintadas com melanicos. Ciencias Biol., Secao 5, Zoologica H.5: 369-370.

_______. 1981. Contribuicao para conhecimento da Panthera onca (Linne) - onca pintada (Mammalia-Carnivora). Cruzamento de exemplares pintadas com melanicos. IV Reuniao da Sociedade de Zoologicos do Brasil.

Diaz, Bernal. 1956. The discovery and conquest of Mexico. Farrar, Straus and Cudahy, New York.

Dittrich, L. 1979. Die vererbung des melanismus bein jaguar (Panthera onca). Zool. Garten N.F., Jena 49(6): 417-428.

Dixon, J. 1979. Origin and distribution of reptiles in lowland tropical rainforests of South America. In Duellman, W. (ed.) The South American herpetofauna: its origin, evolution, and dispersal. Univ. Kansas Mus. Nat. Hist., Monograph 7: 217-240.

Duellman, W. 1979. The herpetofauna of the Andes: Patterns of distribution, origin, differentiation, and present communities. In Duellman, W. (ed.). The South American herpetofauna: its origin, evolution, and dispersal. Univ. Kansas Mus. Nat. Hist., Monograph 7: 371-459.

Duguid, J. 1932. Tiger-man. National Travel Club, New York.

Guggisberg, C. 1975. Wild cats of the world. David and Charles, Newton Abbot, London.

Haffer, J. 1979. Quaternary biogeography of tropical lowland South America. In Duellman, W. (ed.). The South American herpetofauna: its origin, evolution, and dispersal. Univ. Kansas Mus. Nat. Hist., Monograph 7: 107-140.

Humboldt, A. von. 1853. Personal narrative of travels to the equinoctal regions of
America during 1799-1804. London.

Leopold, A.S. 1959. Wildlife of Mexico. Univ. Calif. Press, Berkeley, 568 p.

Lynch, J. 1979. The amphibians of the lowland tropical rainforests. In Duellman W. (ed.).
The South American herpetofauna: its origin, evolution, and dispersal. Univ. Kansas Mus. Nat. Hist, Monograph 7: 189-215.

Martin, R. and S. Webb. 1974. Late Pleistocene mammals from Devil's Den Fauna, Levy County. In Webb, S. (ed.) Pleistocene mammals of Florida. Univ. Florida Press, Gainesville.

Mondolfi, E. and R. Hoogesteijn. 1982. Biology and status of the jaguar in Venezuela. International Cat Symposium, Texas A&I University, October, 1982.

Nowak, R. 1991. Walker's Mammals of the World. (5th ed.), Vol. II. Johns Hopkins Univ. Press, Baltimore, 1629 p.

Perry, R. 1970. The world of the jaguar. Newton-Abbot, New York.

Poeppig, E. 1835-36. Reise in Chile, Peru und auf den Amazonenstrome waehrend der jahre 1827-32. Leipzig.

Rengger, J. 1830. Naturgeschichte der saugerteire von Paraguay. Basel.

Rivero-Blanco, C. and J. Dixon. 1979. Origin and distribution of the herpetofauna of the dry lowland regions of northern South America. In Duellman, W. (ed.) The South American herpetofauna: its origin, evolution, and dispersal. Univ. Kansas Mus. Nat. Hist., Monograph 7: 281-298.

Robinson, R. 1970. Inheritance of the black form of the leopard, Panthera pardus. Genetica 41: 190-197.

Roosevelt, T. 1926. Through the Brazilian wilderness. Schribner's, New York.

Shoumatoff, A. The Rivers Amazon. Sierra Club Books, San Francisco.

Sick, H. 1961. Tucani. Editorial Labor, Barcelona.

Simpson, B. 1979. Quaternary biogeography of the high montane regions of South America. In Duellman, W. (ed.) The South American herpetofauna: its origin, evolution, and dispersal. Univ. Kansas Mus. Nat. Hist., Monograph 7: 157-188.

Simpson, G. 1980. Splendid isolation. The curious history of South American mammals. Yale Univ. Press, New Haven.

Smith, N. 1976. Spotted cats and the Amazon skin trade. Oryx 13(4): 362-371.

Swank, W. and J. Teer. 1989. Status of the jaguar - 1987. Oryx 23: 14-21.

Thornbeck, J. and M. Jenkins (ed.). 1982. IUCN Red Data Book. Part 1. IUCN, Gland, Switzerland.

Wavrin, Marquis de. 1939. Les betes sauvages de l'Amazonie. Paris.


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