Jackalope disease is the colloquial term for a rare but striking viral infection in rabbits caused by the Cottontail Rabbit Papillomavirus (CRPV), also known as the Shope papilloma virus. This condition results in keratinised, wart-like tumours that can resemble horns or antlers sprouting from the head, face, or neck of the rabbit. While these growths have contributed to the enduring jackalope folklore in North America, the reality is far from whimsical—this is a serious and sometimes fatal disease for affected animals.
Origins of the Jackalope Legend and the Link to CRPV
The jackalope—a mythical horned rabbit—has long been a part of American frontier folklore and earlier European tales of horned hares. It is believed that sightings of wild rabbits with Shope papilloma virus tumours gave rise to these legends. Early hunters, upon capturing or spotting infected rabbits, would see antler-like protrusions and pass along exaggerated tales that became embedded in local culture.
While the jackalope remains a humorous and light-hearted cryptid in popular culture, the disease behind it is a documented and scientifically significant viral infection with serious health consequences for rabbits.
Understanding the Cottontail Rabbit Papillomavirus
Cottontail Rabbit Papillomavirus (CRPV) is a DNA virus within the papillomavirus family, closely related to certain viruses that cause warts and cancers in other species. First described in 1933 by Dr. Richard E. Shope, this virus was pivotal in proving that some cancers can be caused by infectious agents, revolutionising cancer research and paving the way for developments in human papillomavirus (HPV) vaccines.
The virus is species-specific and infects primarily wild cottontail rabbits, but domestic rabbits can also contract it under certain conditions.
Transmission and Spread of Jackalope Disease
The spread of CRPV occurs through two main routes:
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Vector Transmission – The most common pathway is via biting insects, including mosquitoes, ticks, and fleas. These vectors carry the virus from one rabbit to another, depositing it onto broken skin.
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Direct Contact – The virus can also spread between rabbits through grooming, fighting, or shared resources such as food, water bowls, or bedding. This is more common in enclosed environments where animals have close and frequent contact.
Environmental factors such as warm, humid conditions can increase insect activity and therefore raise the risk of viral transmission.
Symptoms and Visual Indicators
The hallmark symptom of jackalope disease is the development of hard, keratinised tumours that resemble horns or tentacles. These typically occur on:
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The mouth and lips
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Around the eyes
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On the cheeks and head
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Occasionally, other parts of the body
Other signs may include:
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Difficulty eating or drinking due to obstructive growths
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Impaired vision if tumours cover or press on the eyes
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Weight loss from reduced feeding ability
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Secondary infections caused by open wounds or irritated skin
In mild cases, the growths may remain small and eventually regress naturally, but in severe infections, they can reach several centimetres in length and cause extreme discomfort.
