Jaculus, Rochester Bestiary, c.1230

The jaculus is a fearsome creature of ancient myth, described as a flying snake with deadly speed and precision. The Roman poet Lucan famously referenced this snake in his epic poem, the Pharsalia, vividly capturing the terrifying nature of these “flying iaculi.”

According to ancient descriptions, the jaculus is not just any ordinary serpent. It lies coiled high among the branches of trees, waiting with patient cunning for its unsuspecting prey. When an animal passes by beneath, the jaculus strikes with lightning speed, launching itself like a javelin — a fitting name since iăcŭlum derives from the Latin verb iăcĕre meaning to throw. This airborne assault is swift and deadly, as the snake propels itself through the air, colliding with its target and delivering a fatal blow.

The jaculus’s terrifying reputation has fuelled its symbolism as a creature of sudden danger, embodying the unpredictability of death striking from above. It represents not just a literal serpent but also a metaphorical embodiment of stealth, speed, and lethal precision. Whether in literature, art or medieval bestiaries, the jaculus has endured as a powerful symbol of nature’s more unpredictable and deadly elements, lurking just out of sight, ready to strike without warning.

Iaculus serpens est. volans. de quo lucanus. Iaculique
volantes. Exiliunt enim in arboribus. et dum ali-
quod animal obvium fuerit; iactant se super illud
et perimunt. Unde et iaculi dicti sunt.

The jaculus[1], iăcŭlus[2], is a flying snake, as mentioned by Lucan: “and the flying iaculi. They leap out of trees and whenever any animal happens to pass by, they throw themselves onto it and kill it. Hence, they are called jaculi."[3]

Endnotes

[1] In reality, there is a species of boa called eryx jaculus, known commonly as the javelin sand boa. https://en.wikipedia.org/wiki/Eryx_jaculus

[2] In Latin, iăcŭlum means also javelin. https://en.wikipedia.org/wiki/Jaculus

[3] Lucan, Civil War 9.720: “And the flying iaculi, for they spring up into trees, and whenever some animal happens by they throw (iactare) themselves on it and kill it, whence they are called iaculus”.

Further Reading

David Badke, The Bestiary Blog: Animals in the Middle Ages, Jaculus, November 6 2023, https://bestiary.ca/beasts/beast273.htm

Josh Goldenberg (BA 2012) and Matt Shanahan (BA 2014, Logeion, November 2022, https://logeion.uchicago.edu/

Castiglioni, L. and Mariotti, S. (1996). Vocabolario della Lingua Latina: Latino-Italiano Italiano-Latino. Terza Edizione. Loescher Torino

Wikimedia Foundation, Inc., Wikipedia: The Elephant, 28 November 2023, https://en.wikipedia.org/wiki/Elephant

Matthews, J. and Matthews C., (2010), The Element Encyclopedia of Magical Creatures, HarperCollins UK, London

Curley, M. J., Physiologus: A Medieval Book of Nature Lore (University of Chicago edition 2009)

Rackham, H., M.A., Pliny Natural History Volume III, Libri VIII-XI (London: William Heinemann Ltd, 1949)

Collins, A. H., M.A., Symbolism of Animals and Birds (New York: McBride, Nast & Company, 1913)

Henderson, C., The Book of Barely Imagined Beings (London: University of Chicago Press, 2013)

White, T. H., The Bestiary: A Book of Beasts (New York: G.P Putnam’s Sons, 1960)

Barney, S. A., Lewis, W. J., Beach A., Berghof O., The Etymologies of Isidore of Seville (New York: Cambridge University Press, 2006)