The Body Design of Hagfishes (Eptatretus stoutii and Myxine glutinosa) Protects from Biting Predators

Boggett, Sarah
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University of Guelph

This thesis investigates how the body structure of hagfishes plays a role in defence against biting predators. Evidence of hagfish being attacked by biting predators show them swimming away relatively unscathed even after a violent initial attack. I hypothesized that the flaccid and loose body design of hagfishes protects them from biting predators by the minimal attachments between the skin and musculature combined with a large subcutaneous sinus allowing its internal organs to avoid damage from penetrating teeth. To test this, I quantified the flaccidity of the subcutaneous sinus, simulated shark attacks with a customized guillotine, and manipulated the adhesion and flaccidity between the skin and body of hagfishes and lamprey. Here I provide evidence consistent with my hypothesis. This ability of hagfishes to survive initial attacks from biting predators may be an essential component of a strategy that relies on defensive slime to thwart further attacks.

hagfish, shark, subcutaneous sinus, predator, prey, skin, loose, flaccid