Sunday, January 4, 2015

Stubby, Bobtail, Dumplings

Mollusks. Generally they're not a particularly cuddly bunch. For example, most people wouldn't call the inside of an oyster cute.

"D'aaaww who's a good boy?"
Courtesy: Larry Hoffman via Flickr

But there is one group among the mollusks that stands apart. The sepiolidae (pronounced seep-ee-oli-day) are an order of mollusks related to squid, octopus, and cuttlefish. More commonly these animals are called stubby, bobtail, or dumpling squid. None of the stubby squids get much bigger than around ten centimeters (about half the length of an unsharpened pencil), so they're round and small, which makes all of their common names very appropriate. The squid part of the name is a little misleading however because these animals show characteristics consistent with all of their cousins. They spend most of their lives on the bottom, like octopus; they have eight arms and two tentacles, like squid; and they have short rounded mantles, like cuttlefish. 

Who do you think you are? No, seriously I can't figure it out.
A Hummingbird bobtail (Euprymna berryi)
Courtesy: rtonyr via Flickr

Sepiolids are most closely related to cuttlefish which many people guess by the brilliant colors they can produce. Don't let the flashy get up fool you though; stubby squid are some of the best hiders out there. Not only can they change those colors to better match their surroundings, they're also master excavators.

Sepiolids are so cute that they even snuggle up in a blanket to sleep. They dig down by using their siphon (a tube coming from their body that they use to swim and breathe out.) to force water into the bottom and create a little depression. Then they settle down into it and use their arms to wrap themselves in a nice blanket of mud, leaving only their head sticking out.

Makes sense, you've got to wrap a dumpling 
to steam it properly
Courtesy: Nick Hobgood via Flikr

They spend most of the daylight hours tucked in deep water in their sandy beds and come out at night to hunt. Once they're on the prowl they'll often move to shallower water where they're sometimes encountered by lucky divers. 

So if they're this adorable as adults what do their babies look like? Well pretty much exactly like their parents. Dumpling squid have smaller egg clutches than many of their relatives. They lay up to about 50 eggs, which compared to a giant Pacific octopus' max of 100,000 is practically nothing. And unlike many of their relatives' babies, stubby squid don't spend time as a part of the plankton. The young sepiolids break out of their egg cases ready to roll, and walk away to find some food.

The eggs of the Pacific stubby squid (Rossia Pacifica
Courtesy: Chris Wilson via Flickr

You'd think that because these animals are so cute and charismatic that we'd know a lot about them. But because they live at the low end of recreational dive limits, are nocturnal, bury themselves, and tend to live on sandy bottoms which divers often ignore, we actually know very little about the lives of these cool little animals.

References:

Rodrigues et al., "Burying Behavior in the Bobtail Squid Sepiola atlantica (Cephalopda: Sepiolidae)", Italian Journal of Zoology, Apr 06, 2010

Anderson, Roland C.,  "Rossia Pacifica, Stubby Squid", The Cephalopod Page,

2 comments:

  1. Patrick--
    I ate one when I was in Japan in December. I apologize to all sepiolids. In my defense, it was part of a fixed menu of traditional local food at an inn I stayed at. So I didn't actually ask to eat it. And of course I took good photos so I could try to ID it later.
    Steff

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  2. Steff,

    I fully believe that humans, as omnivores, have a right to eat other organisms if they so choose. So you are karmically sound as far as I'm concerned. Did you ever manage to ID it? I imagine if it was cooked that would have made it more difficult.

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