Invasion of the Tree Octopus!
Hey everyone! This is Nora, the intern here at Wahkeena. Robyn will be out of town for the next couple of weeks so I will be the one discussing a new species to the preserve!
We found a Tree Octopus this spring here at Wahkeena, and later identified it to be Polypoda arborialis. Which is an eastern species of Tree Octopus that is closely related to the Pacific Tree Octopus. Since the first was found, several others have been recorded throughout the Preserve.
Tree Octopi are ‘amphibious,’ meaning that they only spend the early part of their lives, and the mating season in the water, which is similar to several species of salamanders. These solitary cephalopods prefer humid, dense woodlands that remain moist, so as to not dry out. If their skin does begin to dry, the octopus will search out streams, ponds, other small bodies of water, or they may bury themselves in moist soil.
In springtime, the Tree Octopus will return to the body of water in which it matured. There, they congregate and find a mate. After a brief courtship display, the male deposits a sperm packet into the female using a specialized arm used only for mating. After fertilization, the female will attach the eggs to herself and defend them for 17-21 days until just before the eggs hatch. She releases the eggs one by one, and they float away in the water. Scientists believe that separation of the eggs results in less competition for the baby octopi and a higher success rate for the species. Even so, the mortality rate is very high. Females lay between 1,000 and 2,500 eggs. Out of that number, only about 2% of those Octopi live to reach adulthood. Tree Octopi are endangered due to water pollution, inbreeding, and over harvesting for sale in markets overseas.
You should stop out to Wahkeena soon, so you can catch a glimpse of these mysterious creatures before they head to hollow trees in the fall to wait out chilly weather.
Remember! Tree Octopi are not pets! If kept in dry environments, they will deteriorate and quickly die. They will not hurt you if handled, but be sure to return them to the proper habitat!