Meeting Abstract
Hagfishes are able to squeeze through small openings to gain entry to crevices, burrows, hagfish traps, and carcasses, but little is known about how they do this, or what the limits of this ability are. In order to describe this ability, and to investigate possible mechanisms by which it is accomplished, we analyzed videos of Atlantic hagfish (Myxine glutinosa) and Pacific hagfish (Eptatretus stoutii) moving through narrow apertures in the lab. We investigated the hypothesis that the passive movement of blood within a hagfish’s flaccid subcutaneous sinus allows it to squeeze through narrower apertures than it would be able to if it were turgid. To test this hypothesis, we measured changes in body width as the animals moved through narrow openings, and documented the behaviors associated with this ability. We found that hagfishes are able to pass through narrow slits that are less than one third the width of their bodies. Our results are consistent with the idea that a flaccid subcutaneous sinus allows hagfish to squeeze through narrow apertures by facilitating a rapid redistribution of venous blood. In addition, we describe nine distinct behaviors associated with this ability, including a form of non-undulatory locomotion also seen in snakes and lampreys. These results have relevance for the hagfish trap fishery and they illuminate a behavior that may be a critical component of the hagfish niche, due to its likely importance in feeding and evading predators.
