Going Up or Sideways? Perception of Space and Obstacles Negotiating by Cuttlefish

While octopuses are mostly benthic animals, and squid prefer the open waters, cuttlefish present a special intermediate stage. Although their body structure resembles that of a squid, in many cases their behavior is mostly benthic. To test cuttlefish's preference in the use of space, we trained juvenile Sepia gibba and Sepia officinalis cuttlefish to reach a shelter at the opposite side of a tank. Afterwards, rock barriers were placed between the starting point and the shelter. In one experiment, direct paths were available both through the sand and over the rocks. In a second experiment the direct path was blocked by small rocks requiring a short detour to by-pass. In the third experiment instead, the only direct path available was over the rocks; or else to reach the goal via an exclusively horizontal path a longer detour would have to be selected. We showed that cuttlefish prefer to move horizontally when a direct route or a short detour path is available close to the ground; however when faced with significant obstacles they can and would preferentially choose a more direct path requiring a vertical movement over a longer exclusively horizontal path. Therefore, cuttlefish appear to be predominantly benthic dwellers that prefer to stay near the bottom. Nonetheless, they do view and utilize the vertical space in their daily movements where it plays a role in night foraging, obstacles negotiation and movement in their home-range.

Spatial learning in the cuttlefish Sepia officinalis: preference for vertical over horizontal information

The world is three-dimensional; hence, even surface-bound animals need to learn vertical spatial information. Separate encoding of vertical and horizontal spatial information seems to be the common strategy regardless of the locomotory style of animals. However, a difference seems to exist in the way freely moving species, such as fish, learn and integrate spatial information as opposed to surface-bound species, which prioritize the horizontal dimension and encode it with a higher resolution. Thus, the locomotory style of an animal may shape how spatial information is learned and prioritized. An alternative hypothesis relates the preference for vertical information to the ability to sense hydrostatic pressure, a prominent cue unique to this dimension. Cuttlefish are mostly benthic animals, but they can move freely in a volume. Therefore, they present an optimal model to examine these hypotheses. We tested whether cuttlefish could separately recall the vertical and horizontal components of a learned two-dimensional target, and whether they have a preference for vertical or horizontal information. Sepia officinalis cuttlefish were trained to select one of two visual cues set along a 45 deg diagonal. The animals were then tested with the two visual cues arranged in a horizontal, vertical or opposite 45 deg configuration. We found that cuttlefish use vertical and horizontal spatial cues separately, and that they prefer vertical information to horizontal information. We propose that, as in fish, the availability of hydrostatic pressure, combined with the ecological value of vertical movements, determines the importance of vertical information.

[Multiple lipomatosis or Launois-Bensaude disease. Technics for surgical treatment in our clinical experience]

Only 200 cases of this extremely rare disease of unknown etiology have been reported in the literature. The paper examines the various surgical techniques and describes two cases operated by the authors.