It is time to take a minute to relax again. Sit back and enjoy the mesmerising beauty of a Long-arm Octopus (Abdopus sp.). Even though this octopus is quite common in the Philippines and Indonesia, it hasn’t been scientifically described yet. Hence, its scientific name just ends in sp. for species. As there is another long-armed octopus in the Atlantic (Macrotritopus defilippi), our cephalopod is often called a White V octopus instead.
Take a minute with Long-arm Octopus (Abdopus sp.)
Abdopus sp. likes living around (black) sand slopes with mild currents. The head of this octopus is usually around 6 cm in size, while the arms can reach 15 cm in length. These long arms are marked with a series of white spots on the body and a “V” shaped mark on the back of the head. Generally, they are coloured light brown to brownish red. When this octopus is resting inside a small hole in the sand, usually only its head sticks out. In general, long-arm octopuses are quite shy. Yes, it is octopuses, not octopi (Let’s talk scientifically: Pictures and classifications of marine life).
In this case, we were lucky enough to meet the long-arm octopus (Abdopus sp.) while it was out and about searching for food. Same as mimic octopus which is closely related to them, the long-arm cruises along the bottom in a teardrop shape.
We love octopuses
We wrote a long story on the body, brain and nervous system of octopuses in „Take a Minute XXI: Coconut Octopus (Amphioctopus marginatus)“ as well as what they eat and how they mate. Therefore, we focus on other aspects regarding their arms now. First of all, octopuses have arms, not tentacles. There are other cephalopods with tentacles such as cuttlefish (Savvy softies: Octopus, cuttlefish and squid), but an octopus is all about arms! More precisely, eight arms. Hence, the name octo (Greek for eight). Even though it was called a foot first (pus from pous for foot).
Maybe, feet turned into arms when people observed what an octopus can do with them. Each arm has around 280 suckers (~2,240 suckers in total). They are used for: Moving, pushing, pulling, grasping, camouflage, mimicry, fighting, mating, capturing prey and tasting.
When an octopus sustains an arm wound, they don’t get a scab or scar as we would. Instead, a layer of cells called epithelium (the same cells that make up our skin layer) covers the wound and beneath this, the regeneration process begins. A study reported that the first sign of regeneration came in the form of a tiny knob on the arm edge, 3 days after injury. After 11 days, they observed a protrusion which turned into a hook-like structure by day 17. By day 55, a complete structure (mini arm) was visible and by day 130, the new arm tip had fully regenerated.OctoNation: Here’s everything you need to know about octopus arms
Defence and offence of a Long-arm Octopus (Abdopus sp.)
Some species of octopus can even drop an arm to confuse a predator. It can keep moving for up to five hours. This defence tactic is called “arm dropping” and apparently some String-Armed Octopuses manage just fine with only 2 arms! However, this species can regenerate its arms as quickly as 6-8 weeks.
For hunting, octopuses use an arm or more to feel out the nooks and crannies in the reef and grab anything wanting to escape with another one. A different technique is net fishing. In this hunting strategy, the octopus spans its whole body over a small piece of coral or such. Only when it has blocked all escape routes, it starts poking around with its arm to get its prey out of hiding and into the net with eight arms. The longer the arm, the easier the catch? Possibly.
Connect and protect
We hope there will be more studies on this interesting marine creature soon. Subscribe to our channel for more ocean stories.
Besides, we ask for your help in the name of octopuses. Spain plans to set up the first worldwide octopus farm. Usually, industrial farming leads to problems, be it inside the ocean or on land. Read more on this project and its problems and put our name down against octopus farming here. What to amplify your voice? There are more petitions out there: here and here. Let’s care and share!
Want to relax a little more?
For more visual meditation and marine information, watch the whole playlist on our YouTube channel or browse through the different clips on our designated page „Take a Minute“ on this website or in the blog.