Wondering about mimics?

I have been meaning to write a blog about the Mimic octopus (Thaumoctopus mimicus) and Wunderpus (Wunderpus photogenicus) for ages, but inspiration has eluded me until I was revisiting some of my earlier research on charismatic muck dive species. Both the mimic octopus and the wunderpus are very popular with critter enthusiasts, but we know surprisingly little about them. Time to change that or at the very least tell you some of the things we know about them!

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A wunderpus (Wunderpus photogenicus) checks out my camera

If you’re not a diver or you have never heard of them, the Mimic and the Wunderpus are very (very!) funky species of octopus. They have a wide range of interesting behaviour, they look amazing, and both are found on sandy habitats in the tropics. What they also have in common is that both were only recognised as new species fairly recently (2005 and 2006).

Just by reading their scientific names you could imagine these are not your average cephalopod. The wunderpus’ species name “Wunderpus photogenicus” says it all and  is probably also one of the easiest scientific names to remember (except maybe for the brilliantly named “Boops boops“). “Thaumoctopus mimicus” tells you that this particular species is good at mimicry, even for octopus standards.

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Mimic octopus (Thaumoctopus mimicus) foraging on the sand

Both species live on soft sediment (mostly sand) habitats and they have evolved to be perfectly adapted to this lifestyle. They live in holes in the sand, are small, have longer arms than your average octopus, and their colours are quite drab. There are a few subtle physical and behavioural differences between the two though.

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Wunderpus partially in its hidey-hole

One of the things I noticed is that their hunting strategies vary slightly. Wunderpus have more extensive “webbing” between their arms than mimics and they use this webbing when hunting. Crabs are a favourite prey of wunderpus and they catch them by spreading their mantle (the “web” between their arms) over rocks, holes, or other objects like a big parachute. They then use the tips of their arms to poke the crabs out of their holes, after which they run into the parachute-web and are easily collected with one of the other arms.

Mimic octopus seem to forage more actively and (in my experience) use the parachute-technique less often. Instead they poke their long arms into holes in the sand, scaring out any critter that’s in there and then grabbing it directly. This means that mimics spend even more time moving over the sand than wunderpus do, which might be why they evolved some very particular behaviour.

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Trying to mimic?

Whenever you search for information about the mimic octopus, one of the first things to come up is that they mimic all kinds of other animals. Unlike other octopuses, it does not just mimic colour, but also the behaviour of up to 6 (or 8 or 12 depending on who you ask). The question is, does a mimic really mimic? Their mimicry is supposed to deter or fool predators or prey, but I wonder if this is really the case, or whether we are over-interpreting things from our human perspective.

Many of the behaviours that have been called mimicry could also be explained by simple logic or physics. Take for instance the idea that they mimic toxic flounders/soles while swimming. Yes, they do look very similar when they swim, but it is also a fast and energy-efficient way to swim over any flat area. Which is undoubtedly why this type of swimming is used by most octopus species living in the sand. Another example is the lionfish-mimic, which could also be explained as a way to look as big as possible when threatened. It’s a very common tactic used throughout the animal kingdom, and if you happen to be an octopus with long arms, you’ll look like a spiky lionfish when spreading them out. Other behaviours can similarly be explained, but I wouldn’t want to bore you with long lists right now.

Does this mean they do not mimic or that I am just a mopey cynical bastard who refuses to be amazed by a fantastic animal? Of course not! I love mimics and they show some  of the most extraordinary behaviour in the ocean. It just means that I want to learn more about them to find out what causes it.

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Close up of a mimic octopus

To study them properly, you first need to be able to tell the wunderpus and mimic octopus apart though! These critters look very similar (stripey), so it’s easy to get confused. Here is what to look for:

  • Arm patterns I: The black/white patterns on the arms of Wunderpus are very sharply defined, compared to more blurry with the mimic. Imagine the patterns on the wunderpus were drawn by a German painter using a pen and ruler, and the ones of the mimic by me with some crayons.
  • Arm patterns II: Mimic octopus have a continuous white outline along the border of each arm. The wunderpus does not have this, instead the band-pattern continues across the border.
  • Head: Mimics have a “U-“-shape on the back of their head, where wunderpus have a white patch.
  • Colour: Wunderpus usually have more of a red/brown colour shade to them than mimics, which are almost always black and white. Careful though, they can both change colour so this is not the best way of telling them apart.
  • Behaviour: The hunting behaviour I described earlier is a hint, though not always consistent. From my experience, wunderpus live in areas where the sand is more coarse (gravelly) than mimic octopus, which could also explain why they have slightly different hunting methods.

Finally, because you made it this far, here is a video I took of mating mimic octopus in Indonesia:

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Closing one chapter and opening another

It is time to share some very big news. My time in Australia has officially come to an end and I am starting a new and exciting chapter on the other side of the world. From April onward I will officially become a “Research Fellow in Quantitative Tropical Marine Ecology” at the University of Leeds in the UK. In other words, for the next two years I will work as a postdoctoral researcher on a very exciting new project.

I will write about the new project in more detail soon, but right now I am feeling a bit nostalgic about the past 6 years of living and becoming a scientist in Australia .

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Celebrating the end of an experiment on the Great Barrier Reef

I arrived in Australia as a dive instructor, thinking I’d be there for a few months to help out a good friend with a research project on cleaner wrasses in the Great Barrier Reef. Working and living on Lizard Island Research Station gave me the chance to meet some amazing marine scientists passionate about their research. More than anything else, the people I met there are what pushed me in the direction of becoming a marine scientist.

A series of fortunate events lead me to Perth and I somehow managed to convince Professor Euan Harvey that taking on a semi-nomadic beach bum for a student would be a great idea. To this day I still do not know if  Euan was being very wise or very stupid, but once I got my foot in the door of the Fish Ecology Lab it took them about 6 years to get me out again.

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The amazing team of the Fish Ecology Lab, all of you will be missed!

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Happy sunset drinks by the beach

While I never planned on spending a long time in Australia, it didn’t take me long to appreciate the beauty of the place. Western Australia in particular is basically a Europe-sized playground for people who love the outdoors. I can’t count how many camping trips, dives, surf sessions, ocean swims, hikes, … I’ve done in recent years and I still haven’t seen half of what I’d want to see. Some of the highlights that come to mind include camping on remote beaches, diving with seadragons, snorkeling with sea lions, and sunrise surf sessions with friends. I won’t even begin to write about the many wine tasting sessions down south 🙂

I was lucky enough to meet some amazing people along my journey. Almost without noticing it, I built up a group of colleagues and friends. I love the typical Australian easy-going, honest (sometimes in-your-face) style of communication. Even if it could not be more different from what I was used to in Indonesia (or even Belgium). The people more than anything is what make or break a place, and I will miss the ones I left behind in Perth dearly.

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Exploring the coastline in southern Western Australia

When I arrived in Australia I never expected that it would become a second home, but that is exactly what happened. The people, the wildlife, the landscapes, all of it have found a spot in my heart, and I am grateful for my time there. I am very much looking forward to starting a new chapter, if it’s even half as good as the last one it is going to be fantastic.

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See you next time Australia!