in my lab now focuses on the
giant Pacific octopus in three main
areas: behavior, learning, and fisheries.
more about cephalopods, please contact me!
Cephalopods are beautiful animals that
display complex and fascinating behavior. They have existed for about 500
million years and have fascinated humans for thousands of years. One of the
first to study them was Aristotle, who described how octopuses change color.
Today, cephalopods are targeted in large fisheries around the world. They are
also studied for both basic and applied research.
What is a Cephalopod?
Cephalopods belong to the phylum Mollusca.
originated during the Cambrian period (541-485 million years ago (mya)). The
early cephalopods were very small, with slightly curved shells, and occurred
only in shallow seas, but they expanded their distribution during the Great
Ordovician Biodiversity Event (485-443 mya). Today, there are about 790 species in
two sub-classes: Coleoidea and Nautiloidea. The Coleoidea comprise two superorders: Octopodiformes
A remarkable feature of cephalopods is
their complex and beautiful skin. Many species can rapidly change their
appearance quickly. This feature is called Rapid Adaptive Coloration. It
is used for camouflage and communication.
The most important elements in the skin
They are tiny sacs of pigment surrounded by muscles that are under nervous
control, so they can rapidly expand and contract. The color of the pigment may
be red, brown or yellow, depending on development and species.
many species, the chomatophores overlie reflective tissue called iridophores, which
Some species also have permanent
white patches just below the iridophores called leucophores.
experiments have shown that cephalopods control their body pattern visually.
For camouflage, they view their surroundings and quickly process the visual
information. Then, the central brain sends neural signals throughout the skin
to chromatophores and iridophores to produce the appropriate body pattern.
This entire process can take less than 200 milliseconds – faster than a blink
of the eye!
addition to the colorful body patterns, octopuses and cuttlefishes can morph
their skin into three-dimensional shapes to enhance camouflage called papillae. No other animal on the planet can do
are fast learners. They have large brains with 34 lobes and millions of
neurons. Yet only one-third of its total number of neurons occur in the brain.
Two-thirds occur in arms, skin and other organs! There is strong evidence in
octopuses and cuttlefishes for both short-term (one hour) and long-term
(several months) memory.
even though they seem smart, it is difficult to assess intelligence. For
example, there is little evidence (so far) that they play or can use tools. And
most cephalopods are not social. Are they really intelligent? More
experimentation is needed!
are an excellent protein source and a popular food around the world, especially
in Asia. During 1999-2015, the world catch of cephalopods increased from 3.4 to
4.7 million tons. Most of the catch is composed of squids (3.5 million tons in
largest squid fishery is Japan is for Japanese
flying squid (Todarodes pacificus).
In 2015, octopus landings were 400,000 tons. The most important species in
Hokkaido is the giant
Pacific octopus (Enteroctopus dofleini).