The Enigmatic Dwarf Marsh Rabbit (Sylvilagus palustrellus) of the Pleistocene

The marsh rabbit (Sylvilagus palustris) ranges throughout Florida and the coastal plain of Georgia, South Carolina, and North Carolina.  Wetlands are their preferred habitat.  During the Pleistocene they co-occurred with a little known related species, the dwarf marsh rabbit (S. palustrellus).  Fossil evidence of the dwarf marsh rabbit has been found at just 3 sites-the Ichetucknee River, Melbourne, and Vero.  All of these fossil sites are located in Florida.

Distribution of Sylvilagus palustris

Range map of the marsh rabbit (Sylvilagus palustris).  A dwarf relative of this species (S. palustrellus) lived in Florida and perhaps the coastal plain as well during the Pleistocene.

Some doubt S. palustrellus is a valid species because there is so little evidence of its former existence.  However, Dennis Ruez, a scientist who teaches at the University of Southern Illinois, is convinced there was  a dwarf marsh rabbit inhabiting late Pleistocene wetlands in Florida.  Dennis Ruez is the only living scientist to really study this species.  He believes the dwarf marsh rabbit was a distinct species from any other species of rabbit because its teeth were “SO much smaller.”  The specimen he examined was an adult lower 3rd pre-molar.  He compared it with the lower 3rd pre-molar of a marsh rabbit and also noticed some distinct differences besides size.  The only illustration of this species is of this tooth in a short paper he authored.  This paper can be accessed via the following link.

The dwarf marsh rabbit may never have been a common species.  Fossil hunters have discovered 22 marsh rabbit teeth in the Ichetucknee River, but only 1 tooth of the dwarf marsh rabbit.  The drastic environmental changes experienced in Florida likely explain the evolutionary history of the dwarf marsh rabbit.  During interglacials sea level rise inundated most of Florida, leaving some marsh rabbits stranded on islands where some populations evolved to a larger or smaller size.  Conversely, during glacials marshes became separated by large dry prairies unsuitable for marsh rabbits and some populations evolved differing sizes following these isolating events.  The uncommon smaller species was more vulnerable to extinction through disease or predation.  It’s 1 of the few small mammal species to become extinct at the end of the Pleistocene.

There are 3 extant subspecies of marsh rabbit.  The lower keys marsh rabbit (S. palustris hefneri) lives on Key West and is in danger of extinction there because of suburban development and house cats.  This subspecies was named after Hugh Hefner, founder of the Playboy Magazine empire.

AMI's David Pecker Hosts Playboy's 50th Anniversary Celebration

Playboy bunnies.

Working to conserve endangered 'Playboy' bunnies

A real playboy bunny, the lower keys marsh rabbit (Sylvilagus palustris hefneri), a subspecies named after Hugh Hefner, founder of the Playboy magazine empire.


Ruez, Dennis

“Dental Variation in Pleistocene Marsh Rabbits from the Ichetucknee River, Florida”

Current Research in the Pleistocene 2011

Ruez, Dennis

“A New Record of Sylvilagus palustrellus from the Rancholabrean (Late Pleistocene) of Florida”

Current Research in the Pleistocene 2003


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