Why do fish like being stroked?

The aquarium at the Cherbourg submarine museum (highly recommended; wonderful museum to visit, especially with small people) has a petting tank. Where small (and not-so-small) children can stroke the backs of friendly rays. It's a large (but not very deep) tank that's only accessible to said small people on one side, so the rays have to actively swim to the people to be stroked.

Cats, dogs, humans and other furry things like to be stroked, and even the act of stroking can reduce down a stressed-out heartrate, and it makes sense that animals that rely partly on contact senses should benefit from using those senses to communicate maternal presence, safety etc. But then we get to the hairless creatures that also enjoy a tickle behind the ears, including toads (who are also partial to catfood, but that's another story), snakes, and fish, and my question for the day has to be "what do the fish get out of it?".

so, starting with which types of fish and why. Georgia aquarium has bonnethead sharks and cownose rays. Other aquaria mainly feature rays and sharks, with the occasional catfish (and starfish, crab or sea urchins to feel rather than stroke). And Nausicaa claims to have cuddly skates. Now it may be that these fish are easy to put small hands on without causing any damage from fins etc; rays, in particular offer a nice flat back to stroke with the minimum amount of coordination (sometimes a difficult thing when you're 3); maybe it's because these are naturally placid fish, and therefore unlikely to bite anyone (although it does occasionally go wrong, and in the case of the cownose ray, it's because they prefer swimming at the top of the tank rather than lurking at the bottom of the tank like most other types of ray.

Okay, so maybe the fish type is a red herring. But still, the question remains: why do the fish like being stroked? What evolutionary reason could there possibly be for this? OR maybe it's learnt; the touch tank at the Tampa Bay stadium sells ray food to its visitors. Maybe what we have here is simply Pavlov's fish.

Meanwhile, an intriguing nugget: the underwater world at SF's Pier 39 rotates its petting tank inhabitants out of the tank every 3 days because they get "tired out" in the tank. How? Why? The journey continues... To where I find that stingrays in petting tanks have their spines snipped off with pliers so they can't hurt the people stroking them. It's a good thing for us (but not necessarily for them) that they have a reputation for being docile.

Things to do in Seville when you're cold

Yahay! I've found out how to edit posts! Which means that this one will be growing over the next few months, ready for a small trip to yet another favourite place: Andalucia. So, in no particular order for now, things to do in Seville:
Seville itself: eat tapas. Lots of tapas. Seville invented them, it would be rude not to try, and it will be interesting to see how much they differ from the Pintxos in Donostia (that's San Sebastian to non-Basque-speakers). Walk up the Giralda tower, but not if you're a cow (they tend to get stuck in towers). Go to a real flamenco show to see wild young men fight with their feet and tug at your heart with their songs.
Go to Granada: spend at least half a day in the Alhambra, being overawed yet again at the sheer beauty of the place. If you have time (and I've never made it out of the Alhambra in less than a day), go up into the Sierra Nevada mountains: sledge, walk up onto the peaks, wear thick warm clothes and listen to the wind in the rocks then scare yourself with the drive back down to reality.
Stop in at Cordoba: go stand in the Mesquita; try to choose a sunny day when the light streams at the doors then dissipates into serenity amongst the mosque's columns. Sit amongst the orangetrees outside and stare at the light from the other side of the doors. Wander off and look at the roman waterwheels.
Stop in at Carmona: lose yourself wandering around the Roman necropolis.
And some places further afield, for a longer trip:
Ronda: take the back road from Malaga to Ronda (is one of my favourite driving roads); you'll scare yourself silly, but you'll arrive at the top with a huge grin on your face. Walk to the el Tajo gorge and admire the new bridge, then back to the bullring and lunch in the place where they don't serve up the soft bits honest nearby (they do a damn fine lamb there). And if you like shoes, this is a good place...

Where do knitting needles come from?

Ah... another one of those burning questions, like "what's the difference between blue and grey eyes (a genteel reader wishes to know)" or "why does washing stain pink instead of green?"

I knit. Some would say obsessively (although I've got it down to a one-a-year habit now), others would say occasionally (that would be the one-a-week crowd). And I've wondered for a while about just who first worked out that taking a stick and a piece of thread would create something warm, woolly and usually of questionable colour sense. Much is recorded about knitting styles and patterns, but very little is said about the humble needles that created them. So once more on a quest, dear friends...

What I know about knitting needles is this: most British knitting uses two long needles. Some folks in Northern Scotland use one needle and dextrous thumbs. Scandanavians use 4 or 5 short doubled-pointed needles, or two short needles joined by a long string. Lengths vary with taste, as do materials: metal, plastic and bamboo are all common, but needles were originally made from bone. And many of these objects are so frightening or annoying to non-knitters that they are routinely banned from aircraft cabins.

And so to curious research. First, nobody knows when knitting really started, but several sources agree that it wasn't 4th century Egypt or 10th century Scandinavia: things that look like knitting from these periods were really created using a complex form of needlework (as in one needle) known as Naalbinding; wikipedia is delightfully pointed about archeologists who can't tell this from real knitting. The rest of knitting needle history is relatively recent. Straight knitting needles probably happened in the 1800s, double-pointed needles are much older, the first recorded use of the term knitting needle dates to 1598, original needle materials included shell and bone which were replaced by less environmentally sensitive materials, and I have been unable to find any more online information than that on this subject.

The hunt continues, but in the meantime, there's always the knitting cartoon set.

Depression

I'm dealing with depression at the moment. It's annoying that my brain chemistry can sneak up and go awry on me, but it happens, I've recognised it, I have to deal with it, and the more I know, the best chance I have of rebalancing my neurotransmitters.

So, what I know already: depression is a brain chemistry imbalance. It usually happens through a combination of events, sometimes combined with a definite trigger on top of them. It takes a while to set in, and a while again to clear. Unlike a broken leg, it can appear to have healed, even during its worst stages; someone with depression can act and appear perfectly normal until it becomes too stressful to keep up that sane appearance. And unlike most illnesses, it's not contagious, but does affect everyone around the sufferer. So now to research...

Symptoms include empty moods, feelings of sadness, anxiety, hopelessness, fatigue, loss of interest in hobbies/sex, difficulty concentrating, sleep problems, appetite changes, irritability, suicidal thoughts, physical symptoms. Tick.

Most of the sites I've visited have advocated treatment, usually in the form of drugs and counselling. These are probably sensible ways to deal with something this severe. Others suggest ECT, to which I have only one response: no f*ing way. Interestingly, nobody suggests removing the stress triggers that bring on depression, but maybe there's no bad in learning to cope with these being more important than the triggers themselves.

Of the chemicals available, SSRIs are popular: these maintain seratonin levels in the brain, keeping receiver neurons stimulated longer than is usually possible in a depressed brain. These take 3-4 weeks to take effect; they apparently need to be taken for 4-9 months before the chemistry balances itself out again; helpfully, most of the sideeffects are linked to the brain adjusting and disappear relatively quickly. I have tried SSRIs once in the past, and an unlisted but apparently common (at least amongst other SSRI users I have spoken -carefully- to) sideeffect is the "fizzing head" feeling, the main reason that I went cold turkey on the SSRI and swore never to use it again. I may reconsider, if I can find a convincing argument that this symptom is normal and unlikely to damage my brain; after all, I need it for my livelihood! Also interesting is the link between seratonin and carbohydrate metabolism; I haven't found much about this effect yet, but gaining weight may be a small price to pay for happiness.

Alternative treatments include St Johns Wort; this is quite common in places like Germany, but tends to be of most use in mild depression. If it's affecting my life, I'm not sure how mild this depression is.

Counselling can be useful for some people, but I'm not sure about me; I'd need an intelligent counsellor who can deal with quite a complex subject, and I'm not sure there are many of those around. CBT (Cognitive Behaviour Therapy), based around the idea of placing a regular structure on my life, could be very useful, as can regular exercise; these are things that I can put in place for myself now.

So, my getting-out-of-depression shopping list:

• Plan. Try to live a structured life; try regular bed and waking times; 10:30 to 7am seems like a good time to sleep; 7:30 to 4pm a good time to work. Allow for the odd deviation from this, but try to keep a general structure. Prepare for the normal, to allow for the unexpected, e.g. sort out the work wardrobe before each working week.
  
• Exercise. Make sure I get out running and to the gym several times a week.
  
• Identify and reduce stress. Always try to do things on the deltas: keep a list and plan of things to do, negotiate and organise work to be done, negotiate the normal boundaries of every relationship, plan to get out of trouble rather than worrying about it. Consider any changes that need to be made to my life (e.g. job or work pattern changes if needed). But be realistic about this, and remember to prioritise.
  
• Remember my own existence. Do things for myself sometimes. And don't hide from, but talk to the people who care about me.
  
• Consider using SSRIs and/or counselling. It's drastic, but if it's needed, it's needed.
  

And finally, for anyone reading this who cares about me: I will get better, I've done it before, but it will take time. Don't expect me to be suddenly well; there will be good days and bad days whilst I recover, but I am still fundamentally the me that you know and possibly love. It's not really relevant how I became ill, because it was never one thing that made me so, but a combination of many; what's important for me now is recovery. You are able to help me with the shopping list, but there is no obligation for you to; depression is a difficult illness to live near, and I won't think any less of you if you can't.