When it comes to “must see” underwater critters, cephalopods are usually high up on people’s lists. There may be one that has very recently become more sought after than others, the Blanket Octopus.
In the Blanket Octopus family there are 4 different species (Tremoctopus spp.) all of which share pretty much the same characteristics. Their appearances are very similar, their habitats do not vary and the limited behaviours that have been observed are matching.
Unlike other octopus, the Blanket Octopus can only be seen here in Lembeh during Blackwater Dives. Whereas all other known species of octopus live their lives on the seabed either up by shallow reefs or the deepest parts of the ocean, the Blanket Octopus lives its entire life out in the open ocean. They can be found throughout the Pacific, Atlantic and Indo-Pacific Oceans but it is not known whether individuals choose to stay in one area or move freely, migrating long distances.
The fact these octopus live out roaming the open ocean makes them extremely hard to track down, in turn this means there is still lots of knowledge left to be gained. Most of the knowledge we have comes from autopsies done by marine biologists dissecting individuals that have washed up on beaches or caught in fish nets, This however, only really tells us about the anatomy of Blanket Octopuses and not about their behaviour of which scientists are still learning.
For those of you who are not familiar with this species of octopus, you may be wondering just how it gets the name “Blanket” Octopus. The “blanket” of the octopus is the most recognisable feature of these species but can only be seen in the females.
The “blanket” itself is a web of skin that is connected between to dorsal arms of the octopus. Whilst swimming normally, the “blanket” will not be on show and instead will be furled up between its arms as seen in the photo above. However, if she detects a possible danger she will unravel the “blanket” and it will flow behind her.
If the blanket is not enough, this octopus has a few other defense mechanisms, some of which it shares with all other octopus species. Of course, just like other cephalopod species, it is able to change its skin colour in order to camouflage……..camouflage with what exactly, we’re not entirely sure!
But this octopus also has a very cool defensive ability it can use to deter predators. The Blanket Octopus is able to tear off the tentacles of stinging jellyfish species and then use it as a sort of stinging armour. So if the “blanket” was not enough to scare away the threat, the stinging tentacles held in the arms of the octopus would surely do the trick!
As mentioned before, the male does not carry the blanket like females do…..but that is not where the differences end. The females are believed to grow up to from anywhere between 6-7 feet whereas the males are about an inch long, about the size of a walnut! The females can also weigh as much as 40,000 times the weight of the males. This is the largest known difference in size between males and females of the same species, called sexual size dimorphism.
With the massive discrepancy in size, the mating process is a little different as well. When the tiny little male has found a female, he will snap off his hectocotylus (a modified sex arm) and give it to the female who will keep it in her mantle. Once she decides to lay her eggs, she may lay up to 100,000 eggs and fertilise them with the males severed hectocotylus.
The female will continue to care for the eggs, carrying them in a small pouch in one of her arms. The pouch is made of a calcium carbonate material which is the same substance that other molluscs use to make their shells. The pouch then is quite sturdy allowing her to carry on roaming through the open oceans.
Both the male and female are thought to die after the reproduction process. The male, after it has removed its hectocotylus and the female, once the eggs have hatched. But as with much of the information on these octopus, this has not been properly confirmed by scientists yet.
Here at NAD we have been lucky enough to have some sightings of these amazing creatures during our Blackwater Dives but they are extremely rare and you have to be very lucky to spot one. If it’s a male you happen to see, their size and movement will be on par to most of the other creatures you may see during a Blackwater Dive, perhaps making it easier to get a shot! If it’s a female, due to their large size, it can be a challenge getting the entire body in the frame when shooting macro…….as you can see from my photos haha!
Below is an amazing video taken by Simon right on our house reef. Here you can see how a female Blanket Octopus unravels her “blanket” and displays it fully whilst swimming.
Why Dive with NAD-Lembeh Resort?
NAD-Lembeh Resort is a small, owner-operated, photography-oriented dive resort in the Lembeh Strait. We are situated in a private bay on Lembeh Island, away from the hustle and bustle of the mainland. We guarantee a 2:1 guest to guide ratio as standard, which makes for a private dive experience and lots of time to take pictures.
ROOMS & BUNGALOWS
All our rooms (10 Beachfront Rooms, 5 Seaview Bungalows) offer ocean view, air conditioning, hot water, wifi, including full board. Our resort has only few steps, which makes our layout extremely convenient to get from your room to the restaurant, camera room, bar and floating jetty.
Our dive team consists of 15 full-time guides, with over 100 years of combined experience! Air as well as Nitrox and various cylinder sizes (both DIN and Yoke are available onsite).
BOATS & FLOATING JETTY
NAD-Lembeh has 4 large, purpose-built dive boats. Each at around 15m long, they offer lots of space and comfort for the divers. Boats feature onboard toilets, towels, drinks and snacks and first aid/ oxygen.
Our jetty allows our guests dignified and quick boat entries – all our dive boats can be moored simultaneously, so there is no wading through the shallows to get on the boat for the dive!
Our focus at NAD is to take your underwater photography to the next level. We offer 1:1 photo classes and our guides are all proficient with photography, using our rental equipment for fun dives when not diving with guests.
We shoot video up to 8K, along with Nikon/ Canon SLR and mirrorless setups. This gives us a rounded knowledge of all cameras. We are also the go-to location for natural history filming in the Straits.
Our newly renovated, huge camera room offers one work space for each and every guest. The spacious, individual benches with lots of power points were purposely built for underwater photographers. NAD’s dedicated camera room is also the perfect place to work on and edit your pictures.
Several rental cameras and strobes are available onsite. We have basic tools and spare parts in our gift shop in case of minor camera problems as well as a drying cabinet, and computer for you to work on and edit your photos.