West Indian Raccoons: From Endangered Endemics to Invasive Introductions

Raccoons on Guadeloupe. Photo from Wikipedia.

In 1788, the journals of one Johann David Schöpf were published in Germany describing his travels in North America. Upon arriving at New Providence Island in the Bahamas, Schöpf noted the presence there of a healthy population of raccoons, which he noted had become established there as the result of "one or more tame pairs of these droll beasts, brought by the curious from the mainland". An English translation of Schöpf's work was not to appear until 1911, but had it appeared earlier this post may have been somewhat different.

The raccoons of the genus Procyon are generalist omnivorous carnivorans* widespread in North and South America. The two most widespread species of the genus are the North and Central American P. lotor and the South American P. cancrivorus. Four further species have been described from isolated populations on Caribbean islands. All these island populations have restricted ranges, and the Barbados population is most likely extinct. However, recent research has shown this might not be the conservation tragedy it seems to be, as it turns out that the majority of the four "species" are not valid species after all, but human introductions of the North American P. lotor.

*I just love how confusing that sounds.

Helgen et al. (2008) recently published the results of their genetic investigation into three of the four Caribbean "species" - 'Procyon maynardi' from the Bahamas, 'P. minor' from Guadeloupe and 'P. gloveralleni' from Barbados. All three were firmly nested within representatives of raccoons from the eastern and central United States (the fourth species, P. pygmaeus from Cozumel off the coast of southern Mexico, is still regarded as a valid taxon). This finding corroborates earlier studies that found no significant morphological differences between the three island populations and continental populations. What is more, Helgen et al. were able to locate historical records relating to the introductions of two of the three populations. The Bahamas raccoons were the very ones referred to by Schöpf in 1788 (some time before their description as a distinct species in 1898), while the Barbados population was established some time between 1650 and 1680. The origins of the Guadeloupe population are still unknown. Helgen et al. (2008) found that their sampled continental specimens fell into two haplotype clusters, with the Bahamas raccoons among one cluster and the Guadeloupe and Barbados raccoons within another, but there was no clear geographical division between the two clusters.

All three of the original descriptions of the Caribbean populations as distinct species were based on juvenile specimens, and this may have been a factor in their being mistaken for new species. It may have also been the origin of the mistaken belief that specimens of the island populations were smaller than their mainland counterparts. Rather than being conservation targets in their own right, the introduced raccoon populations are a potential cause for concern. This is no small change - in Guadeloupe, the identification of the raccoon population as an endemic species has led to its touting as a flagship species, and the symbol of the Parc National de la Guadeloupe. The removal of its protected status could be an act fraught with political and emotional consequences.

REFERENCES

Helgen, K. M., J. E. Maldonado, D. E. Wilson & S. D. Buckner. 2008. Molecular confirmation of the origin and invasive status of West Indian raccoons. Journal of Mammalogy 89 (2): 282-291.