Data from: Biphasic burrowing in Atlantic hagfish (Myxine limosa)

Myxine limosa is a burrowing species of hagfish that occurs in the western
north Atlantic in areas with muddy substrate and at depths generally
greater than 100 meters. Burrowing of M. limosa has been observed from
submersibles, but little is known about the behavior of these animals
within the substrate or the biomechanical mechanisms involved. Here we
investigated burrowing in M. limosa by observing individuals as they
burrowed through transparent gelatin. A photoelastic setup using crossed
polarizers allowed us to visualize stress development in the gelatin as
the hagfish moved through it. We found that M. limosa created U-shaped
burrows in gelatin using a stereotyped, two-phase burrowing behavior. In
the first (“Thrash”) phase, hagfish drove their head and their anterior
body into the substrate using vigorous sinusoidal swimming movements, with
their head moving side-to-side. In the second (“Wriggle”) phase, swimming
movements ceased, with propulsion coming exclusively from the anterior,
submerged portion of body. The Wriggle phase involved side-to-side head
movements and movements of the submerged part of the body that resembled
the “internal concertina” strategy used by caecilians and uropeltid
snakes. The entire burrowing process took on average 7.6 minutes to
complete and ended with the hagfish’s head protruding from the substrate
and the rest of its body generally concealed. Understanding the burrowing
activities of hagfishes could lead to improved understanding of sediment
turnover in marine benthic habitats, new insights into the reproductive
behavior of hagfishes, or even inspiration for the design of burrowing
robots.