05:40 02-12-2011

Drás Researcher

Hey all! I've been working on my planet project Drás for a bit now, and I had a question about how some of the fauna on Drás breathes. I've attached an image of one of the smaller animals, a traffe, shown in profile. It has 4 sets of 2 legs with 2 pairs offset internally and 2 externally. Anyways, my main idea I wanted to throw out for critique is the idea of "swallowing" air instead of inhale/exhale. It would be very similar to the way we swallow food, except it would have an opening for taking air in and one for letting it out (amusingly found in the rear of the animal where Earth animals have an anus). Let me know how feasible you think this would be

http://i860.photobucket.com/albums/ab170/sweeneypaz/traffe.jpg

09:13 28-11-2011

Jan

According to my amateurish opinion, it would be logical to expect bat flight to be more energy-saving, since they have less efficient lungs. According to this paper http://jeb.biologists.org/content/203/20/3045.full.pdf , bats compensate their inefficiency by the "morphological and physiological factors involved in oxygen uptake and transport and in energy production". But the paper also says that "the high demands for oxygen imposed by flight in an animal with a relatively inefficient tidally ventilated lung (Maina, 1998a) may explain why the heaviest bats, the flying foxes (pteropodids), weigh an order of magnitude less than the heaviest flying birds". So the "deathgleaner" from The Future Is Wild may be impossible

22:17 26-11-2011

SN

Hi Spugpow,

Well I approached this as I do anything in my job as a scientist: what is the source and where is the evidence? The latter is by far the more important one. In this case, the website you mentioned did nit refer to the scientific source, which is always a bad sign (that doesn't reflect on the science, but is does on the journalist: no sources mentioned, poor journalism). I did check the main author who was mentioned, and clearly he/she did intriguing work on bat wings. but in my quick survey I found nothing on the superiority of bat over bird wings. They might be, but I saw no proof; they may also be another approach to obtain magnificent performance, which seems likely to me.
In summary, bat wings are probably as amazing as you would expect them to be; unfortunately, journalism not always lives up to the demands of science.

21:11 25-11-2011

Spugpow

What do you make of this? http://www.livescience.com/1245-bats-efficient-flyers-birds.html

00:13 24-11-2011

Luke

Oh good!

22:29 23-11-2011

SN

Spugpow,

A good question. I wished to overhaul the menu structure first, with a pull-down sytem. I have one working, but I haven't decided yet as it would do away with the chapter headings that I like...

Once that is out of the way, it should not take long...

23:51 22-11-2011

Spugpow

How's the "flying with" page coming along?

18:10 17-11-2011

SN

Jan wrote: "..by manoeuvrability I mean the ability to move backwards as well as forwards"

Aha, well, that's something cloakfish certainly can do!

15:18 17-11-2011

Jan

I never considered cloakfish to be apex predator. And by manoeuvrability I mean the ability to move backwards as well as forwards, if they are similar in this respect to knifefish. Not the best for a long chase, but for a sudden ambush, I think.

22:45 16-11-2011

SN

Jan, Evan, Anthony, it is rewarding to see you all take up the case of the cloakfish with such enthusiasm. One thing I have to comment on is that they are not extremely manoeuvrable: their stiff torso argues a bit against that, causing drag during attempted quick turns. They are, in effect, neither apex predators nor at the bottom rung. There are indeed quite a few variations on the theme.

But where I will take still hinges on their jaws (sorry about that one...), and I haven't clenched the matter yet. I will probably present some more sketches in a few weeks.

16:09 16-11-2011

Jan

Evan Black: No matter how helpless the prey is, cloakfish must compete with other predators for its living. Its most impressive trait, maneuvrability, is a big advantage for a predator hunting by a quick, unexpected attack. Some special tricks are quite expectable here, I think.

I think that developing feeding tentacles would be simpliest solution (maybe from previous filter feeding mechanism) but perhaps that would make cloakfish too similar to cuttlefish. Jaws in the manner of slingjaw wrass would be more complicated to develop, but there would certainly be some osificated material already, so why not turn it into something similar? Basic cloakfish has four jaws, two of them could be protrudable like in wrass and two make the support structure.

15:01 12-11-2011

Evan Black

Excellent point, Anthony.

And I'm all in favor of speculating about adaptive radiation of cloakfish, Jan, or any other clade for that matter, but the important thing to consider is always evolutionary pressure. If a cloakfish is to have a notably different form or feature from its evolutionary kin then what is the environmental impetus? For example, I can readily see adaptations such as poisons, armor, or some kind of camouflage coming about because cloakfish are far from apex predator material. They fit quite well in secondary consumer roles, where the prey they "hunt" is quite helpless in comparison and larger, more dangerous swimmers lurk in the same waters.

More actively predatory roles and adaptations are a bit of a stretch. For example, you included a youtube video of the slingjaw wrass, which can extend its jaw far forward to catch prey. That would be an interesting adaptation for a cloak fish, but developing a convergent structure would take some seriously complex adaptive energy; often that kind of a change requires several stages of adaptation. Perhaps one clade turns from filter feeding to bottom feeding, sifting the sands for food particles that have drifted to the sea floor. Their anterior opening (can we really call it a mouth?) extends into a muscular proboscis, and they siphon particles off the ground. Now we have a structure that could potentially become a protracting prey-catcher.

In short, Jan, when you want to suggest such ideas, and you want others to follow your same line of thought, it's helpful to explicitly walk through the process. Otherwise people are likely to point out that such adaptations aren't as likely to occur as less radical adaptations.

01:56 12-11-2011

Anthony Docimo

Jan - look at salps. or box jellyfish. or hawks. the amount of physical diversity in these quite large groups is not mind-bogglingly huge.

We don't know how large a group the Cloakfish are, but I'd be willing to bet that they weather extinctions better than most groups on Furaha. That in and of itself is a superpower worthy of respect.

15:24 11-11-2011

Jan

I do not want some superorganisms, just to make things more interesting.
If cloakfish are inherently "subnormal", they would not be probably as abundant as "normal" organisms. If they are "normal" and abundant, they would probably make many different forms, some of them "supernormal". The mechanisms for catching prey seem to be quite widespread and diverse among water life, so it is logical to expect some evolution here.
Of course there could be many slow, dump and ineffective cloakfish, but some a bit extraordinary species would make the picture more colorful. Imagine our seas without cephalopods, just with ordinary mollusks. We haven´t simple fishes / some worms division here, we have fishes, cephalopods, birds, mammals, even reptiles competing in the same enviroment.
It is just suggestions, I like to think about these things, but do not need them to be realized.

03:11 11-11-2011

Spugpow

Sigmund: I was referring to the image you linked to depicting the lineages of "fish" on Furaha. You said they'd undergone a remarkable transformation, and I pointed out the changes I thought you'd made.

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