Each arm of an octopus is capable of an autonomous response to light to ensure that it remains hidden when predators are active.
CREDIT: JEFF ROTMAN/ALAMY STOCK PHOTO
Octopuses have remarkable bodies that they stretch and reshape in response to the environment and to the animal's needs. How control over such flexibility is managed is an ongoing question. Work in this area has shown that octopus arms exert a degree of individual control. Katz et al. found that octopus arms display a phototactic response to light, automatically withdrawing when the arm (especially the tip) is illuminated. Unlike previously described photoresponsive cells in the skin of the arms, this response appears to be both autonomic and channeled through the central nervous system. Perhaps, the authors suggest, this allows the arms to be protected from foraging predators during the day, but gives the octopus an override option during their own foraging bouts.
J. Exp. Biol. 10.1242/jeb.237529 (2021).
