CRICKET WORMS: December 1, 2008. I need some help in trying to understand how the system below could have evolved. I just watched it on a science program in graphic detail.

There are apparently large parasitic worms in the south of France that live in crickets and can only reproduce in water. They survive by reprogramming the cricket's brain to cause the cricket to seek out water (often swimming pools) and jump in thus committing suicide. The worms, which are 6 times the length of the cricket but have not incapacitated the cricket, then emerge into the water where they are able to reproduce.

The program showed several examples of crickets making direct beelines for swimming pools from many meters away and jumping in without hesitation. Soon after they landed in the swimming pools the worm would begin emerging from the cricket's abdomen. In any case random jumping would not be efficient enough to perpetuate the reproduction of the worms which must take place in water.

The method of reprogramming the cricket's brain actually involves doubling the number of neurons in the cricket's brain, the new neurons pre-programmed with the new behavior which of course results in the suicide of the cricket. Apparently this involves taking proteins from the cricket, modifying or reprogramming them and transferring them back into the cricket where they migrate into the cricket's brain and form new neurons carrying the malicious code.

Now I can easily understand how once such a system evolves that it is adaptive, but I have enormous difficulty in understanding how it could have evolved in the first place to the point of exhibiting any functionality robust enough to be selected for.

Can anyone help me out on this one? Otherwise I'm going to start rethinking intelligent design!

December 3, 2008. I think I've made some progress in understanding how the cricket worm's behavior might have evolved. My supposition is that the worms must have originally been free living and themselves returned to water to reproduce. This behavior would have been encoded and passed from generation to generation in the worm's DNA. Then when the worms began to parasitize crickets they were somehow able to hack the cricket's brain and transfer the coded behavior to return to water from their DNA to construct new neurons in the cricket's brain that encoded the same software program. Thus the crickets now execute the same program that the worms once did having had it copied into their brains from the cricket's DNA.

Now if this is true there is an extremely IMPORTANT insight here. Namely that the basic software for instinctual behaviors must be basically the same across species! That is the only way software from a worm could run in a cricket's brain. Thus we must assume that it is likely that the basic instinctual software across all species is at least written in the same 'machine language' and is probably is more or less identical code to control the same functions in different species.

I've never heard this theory stated anywhere before but based on the cricket worms it seems highly likely.

I would assume that the basic instinctual or control software (perhaps firmware is a better term?) is stored in the large areas of highly conserved 'junk DNA' which does not encode for proteins (an organism's hardware).

By the basic software I mean the basic instinctual and autonomic programs that drive all species' innate behaviors and maintain homeostasis among its various systems. These would include all of the autonomic control software in the brain that keep an organism's various organs functioning in a balanced way in response to varying conditions. These work through hormonal and the autonomic nervous system that controls things such as heart and respiratory rates.

The basic software would also encode all the primary instinctual behaviors such as the drive to find and eat food when hungry, the desire to reproduce, suckling in infant mammals, the avoidance of predators etc. etc. Basically it is all the code necessary to a newborn animal to be a living being, and that additional code that facilitates the organism to learn (the production of all the additional code the adult organism uses to function) and to store experiential data (to remember).

So I believe the basic software code for such behaviors must be very similar across large families of species. The actual code itself may well be transferrable in many cases with but minor modifications. Then when hard wired into any given species it will manifest according to the particular structure (sensory inputs and modes of action outputs) of that species.

E.g. the seeking water to reproduce code running in the worm's brain would cause the worm to detect water with its particular senses, and move towards the water by wriggling worm locomotion. But the exact same code running in the cricket would cause the cricket to detect water through its very different sensory input system, and move towards the water and jump in by hoping its legs, its completely different mode of locomotion. The code would be the same though the inputs and outputs would differ across species.

As far as I know this is an entirely new EP theory, though I'd be quite interested if anyone has seen anything else along these lines. Any comments would be welcomed on this theory.

ANIMAL MIGRATION: Are animal migrations cultural or instinctual? Likely a combination of both.

Certainly instinctual modes of action are inherited via DNA, they are the original software of any new organism, just as the organism's body is its hardware. The instinct to migrate might be inherited, however I am not familiar with any evidence that actual migration routes are conveyed via DNA. That seems extremely unlikely. Are there any studies where say birds of migrating species raised in isolation migrate by themselves along the traditional routes? I don't think so and would be surprised to hear differently. Genetically transmitted instincts do not consist of memories of specific events, but software instructions for the basic functioning of any organism's (including human) biological hardware.

My impression is that the migration patterns of social animals are cultural behaviors evolved over long time scales, and are continually learned by young from the behaviors of adults.

However in cases such as salmon and sea turtle migration there is obviously no cultural transmission of migration paths since the original exodus does not involve traveling with adults. We must assume that the compulsion to return to birth waters to breed is in fact software transmitted genetically via DNA. That along with a GPS type navigation system most likely based on magnetic field lines and other similar global cues should solve the problem.

Certainly a salmon could not smell the water of a tiny river from thousands of miles away in the ocean. I know that's the usual explanation but I rather doubt rivers smell the same from month to month, much less 30 years later when the salmon return to spawn. GPS is a much more parsimonious explanation. That could be based on magnetic field lines eg. Then when the salmon actually reach the place they were born there could well be some olfactory remembrance involved most likely in combination with local underwater geographic landmarks, patterns of water flow etc.

However I do think that migrations such as those of the wildebeest and caribou which follow available food sources and the seasonal migrations of birds as well are in fact culturally transmitted learning rather than genetic.

A common feature of migration patterns is that individuals tend to return to where they were born to reproduce themselves. This implies there is likely a widespread instinct to do that among species. The basic tension seems to be between locations to have young and better food sources elsewhere at other seasonalities. Migrations are typically between two or more such locations.

One can then assume that the genesis of many migratory patterns is due to gradual long term separations between native birth places and optimal seasonal food sources due to climatic changes. This theory implies a widespread instinct to return to birth locale to reproduce among many species coupled with a natural instinct to roam further and further from the birth local in search of optimal food sources. In some extreme cases this may manifest as a diaspora instinct to roam widely though not enough is known about the travel patterns of species like salmon or sea turtles to confirm that. If such species in fact tend to travel species routes or congregate in specific locales rather than dispersing broadly further explanation would be required.

An additional add on in social animals would be the gradual cultural codification of optimal migration patterns through the optimal survival of individuals which followed those patterns and the passing of such routes down through the generations from adults to young due to the natural instinct of young to follow adults in such species. I think these few elements combined constitute a reasonable theory of migration behaviors as they are seen in the natural world.

KEEPING KOI AND GOLDFISH: I've had two small ponds, totally around 4000 gallons in which I've kept koi and goldfish for many years. Here are some general comments on caring for them. I belong to a couple of newsgroups on the subject and have found there is quite a bit of lack of understanding of basic science in views expressed on the subject. And as usual people tend to become very impassioned in support of their views even when they are obviously unscientific.

First, it is true that all colored koi and goldfish are natural mutations of the original type of the species which have been selectively bred and maintained by humans for their beauty. That is fine as these fish keep their essential body types and are generally quite healthy. However humans have also bred a whole array of extremely disabled mutants as well, mostly in the horrible mutant goldfish types such as bubble eyes etc., but also the butterfly koi. The important difference here is that the colored koi are not disabled, they can swim just fine, while the butterfly koi are all disabled to one degree or other depending on the length of fins, and of course the mutant goldfish even more so.

Orandas are horrible mutants. How can anyone think such gross mutant disability is beautiful seems awfully perverse to me. One suspects that orandas and similar gross mutations are in constant pain and discomfort. In my view all those mutant goldfish should be banned. I cringe when I see them.

To me it's as bad as if people purposely bred Down's syndrome babies, and conjoined twins and kept them as curiosities. What is beautiful to me is nature's designs, not nature's mistakes.....

When I see these poor fish swimming I cringe and feel compassion just as I do when I see a person walking with crutches. To me these mutants are not things of beauty. How can a disabled creature be considered a thing of beauty I ask you? I certainly don't think such creatures should be purposefully bred and find it indicative of something quite perverted in human nature that they are.

Outdoor ornamental fish can be threatened by an array of predators. I've even had a female duck on my pond brutally kill and eat a few 3-4 inch goldfish, perhaps she was loading up on protein prior to egg laying as that behavior is fairly unusual.

Some have asked about wild turkeys and domestic chickens. It is possible a turkey might eat a small fish if was convenient though unlikely. I know chickens will eat pretty much anything that moves and that they can swallow like mice, lizards etc. but neither would normally take anything under the surface of water.

My biggest problems have been with great blue herons. In 2007 I had considerable problems as one and sometimes more would show up ever day and brazenly go after my goldfish. That in itself didn't worry me too much because my goldfish reproduce prolifically and I usually end up moving some to the local lake in Autumn anyway. I would have been more upset if they had gone after the large koi. They are all way too large for them to eat but I've heard of herons just killing larger ones without eating them though I don't know if that's true or not.

My heron (and his buddies) showed up even before first light. I was getting up before dawn every day to go out to see them sitting in the tops of surrounding trees as dim shadows. What finally worked for me was a double string fence close to the pond edge giving the heron no place to stand inside it. That and exploding out my door and throwing light soft bright objects at it and screaming as it took off to scare it but not injure it. After the chick raising season was over the problem stopped. Subsequent years I've had no problem.

I use the stake and lines to deter herons but find one has to do it just right. My herons are smart because they will crouch to go under or step over the lines if they aren't exactly the right height. I find part of the trick is 2 lines, one knee high to them and the other about a foot higher. This pretty much prevents either crouching to go under or stepping over. And also important is to have the lines close enough to the water's edge so the heron can't comfortably stand on the inside of the lines.

Scarecrows don't work for long with herons. Dogs of course are by far the best heron and other predator deterrents but they must have constant access to the pond area.

I also have osprey fly over low sometimes and look down but they have never come all the way down. And one year a kingfisher circled the pond for a couple of days but I never saw him come down to it.

It is sad to hear so many people having problems with their ponds and their fish getting sick and dying. It is tragic that probably most koi people put into their ponds live unhealthy lives and die young. The basic key to maintaining a healthy pond with healthy fish is to make and keep it as natural as possible and emulate a natural healthy ecosystem.

The basic rule here is to make the pool design as natural as possible and use as few chemicals as possible. That means having some mud in the bottom and natural algae on the sides of the pond that the fish, especially the fry can nibble on all year round. And some water plants and hiding places for the fish so they can feel more secure and less stressed.

Natural ponds are continually refreshed by natural streams running through them. Since most ornamental ponds have no natural flow one must first simulate the natural flow with a pump and filter. Generally that flow and filtration must handle a considerably greater volume than the natural flow for an equivalent sized pond to support the much greater density of fish in ornamental ponds.

I tried a couple of filtration systems but now use a Bubble Bead filter with an in pool pump and an ultraviolet (UV) filter downstream from the Bubble Bead filter. The Bubble Bead filters small sediment and muck and has a large surface on which biological filtration can take place to convert wastes. The UV clears floating algae which causes green water quickly and it hasn't come back since I installed it.

The bubble bead does mechanical and biofiltration like a charm. The UV removes green algae like a charm. Together they do everything the pond needs.

BTW you don't actually have to change the UV bulb every year as recommended. That seems to be koi store hype to get you to buy new bulbs. I just finished my 3rd year with the same UV bulb and noticed no difference in green water control.

I must admit I'm continually surprised by people wanting to scrimp a few bucks on their koi systems when each nice koi costs multiple hundreds of dollars. Seems like inconsequential savings to me when that's considered.

I'm very happy with the filter setup I have now. It works great with minimal effort and keeps the water in both of my two ponds quite clear (they are connected by 2 waterfalls and a little stream). Maintenance is very minimal and I've never had any problems with it for the 8 or 9 years I've had it. Previous filter systems I always had some problem or other. I don't even have to do anything special in the fall or spring. Just flush it like I do everyday anyway and leave it as is. Always starts up great the next spring.

I've had plenty of tadpoles with no problems at all. I suspect another reason for your filter problem. I like my frogs and tadpoles, they add interest and sound to the ponds. If it were me I'd welcome them.

Many koi die from disease in outdoor pools. This can be caused either by poor water quality or by diseases introduced with new fish or water plants. Unfortunately fatal koi diseases are widespread among some fish breeders and introducing even one diseased fish without a proper month or more quarantine can lead to the death of all your koi. I had such an unfortunate die off that killed half my koi a number of years ago. Since then I haven't introduced any new fish and I really don't have the room to do so anyway. A UV filter tends to kill or at least diminish any disease that goes through it which is one advantage of having one.

The first and most natural defense which has no side effects is always salt 1 lb up to 3 lbs /100 gallons added gradually over a day. 1 lb has always done it for me. You need to be sure to use pure salt without additives found in some water softener salts. The only problem with salt is that it sometimes kills off nice moss growths.

The key to diagnosing the source of a disease is to consider what's changed recently. If nothing new has been introduced into the pond then it is probably water quality or it is possible that even ducks or water insects might bring something in.

Due to the prevalence of disease in koi ponds there are numerous remedies on the market, but most such chemicals have toxic side effects and can cause worse problems than they cure if they cure. As to Melafix, I've never had that cure anything for me though it smells nice.

I occasionally have a goldfish die of uncertain causes but no die offs since that one koi epidemic. Whatever that was it was self limiting. Make sure to remove the dead fish as soon as possible. I put them out on the lawn and the local fox eats them.

Koi and goldfish often suck in pebbles to move them so they can grub in the muck below. Very occasionally something will get stuck in their mouths that way. I've also had to remove a twig that got stuck in a goldfish'es mouth with tweezers.

Chemical water tests are essential at least until the water chemistry is stablized. Though koi and goldfish can tolerate a range of pH abrupt changes or extreme levels can be fatal. The most common cause of upward spikes in pH is a green algae bloom in the water. Several partial water changes will help but only a UV filter will cure the problem.

All koi keepers need a basic water chemistry test kit to make sure the water is healthy for the fish.

Pool Design. Koi pools should always be in ground not above ground in climates where winter temperatures get cold. Koi should never be kept in aquariums, they are simply much too large and they will be permanently stunted and unhealthy if they survive at all. Koi ponds should be as deep as possible to equalize temperatures and with steep sides to deter predators.

Winter Care: Feeding in winter is one of the most devisive topics that elicts some of the most heated discussions. I feed diminishing amounts of Fall Spring (low protein wheat germ based) food down to around 40 degrees. I've never lost a koi in winter so I know my method works fine. The simple rule I use is I don't stop feeding until I turn my pump off for the winter. I only turn the pump off when the pond starts to freeze over and I put the heaters in instead. That is a quite obvious rule because after the pump is off it can no longer remove the waste from the water from the fish metabolizing food.

Fish feed naturally at reduced levels in all natural ponds and lakes. That is of course THE ONLY REASON that the popular sport of ice fishing is possible! However in many koi ponds if not most there is unfortunately no source of natural winter algae or other vegetative matter. This is a big mistake that many people who raise koi make, namely killing all the algae off the sides of the pond with chemicals. Bad news! Both the algaecide chemicals are bad for the koi and the elimination of the natural algae food source is bad for the koi, especially the smaller ones who don't have as much fat reserves in winter. Especially in those cases it's important to feed minimally later into the winter.

I think the standard winter feeding advice is way over conservative. I feed my koi and goldfish a little even in cold weather until the water freezes over. Just as much as they will eat 2 down to 1 times a day in coldest weather. I do use cold weather low protein food. My philosophy is to respect nature as it usually knows best. As long as the fish feed I figure they know better than all the experts. I have extremely low winter die offs of goldfish and none of koi so the method works fine for me.

The basic issue is this: Any species that had the tendency to overeat itself to death would be extinct long long ago. Therefore assuming healthy food appropriate for the season is available we must assume every organism including koi and goldfish knows best what and how much is best for it to eat, no matter what any 'expert' may say. Give it some thought. Your koi may well thank you for not leaving them excessively hungry during the winter....

The koi's digestive system is somewhat different structurally than the standard stomach of most organisms and doesn't secrete HCL, nor is it defined by sphincters, nevertheless there is an expanded area of the alimentary canal where food is stored and digested which in common parlance is referred to as its stomach. Actually, if I recall my biology correctly, most fish fry have this same primitive structure, and the true stomach only develops later in most fish, but koi retain that structure and never go on to develop a true stomach. However I and everyone else will probably keep on talking about our koi's stomachs for convenience, but it's important to keep in mind the term is not technically correct.

In ponds with good depth in warm weather the bottom will be colder than the top. This is called a temperature inversion and is why the surface freezes but the bottom doesn't. Basically the situation is this, the bottom temp tends to equalize to the temp down in the earth which remains more or less constant all year round, while the surface water tends to equalize to that of the air which changes dramatically with the seasons. The actual average air temp at which a temperature inversion forms in the pond will depend on a number of factors such as pond depth, circulation, temperature zone, volume vs surface area etc. so if would be difficult to state a precise temperature. Here in N. NJ the bottom of my ponds never drops below 39^ even when there is ice on the surface. It will be even warmer on days with bright sunlight.

The main point though is that average temperatures under the earth a few feet in US avg 50-55 degrees, that is why caves for example tend to stay the same temp all year round (unless there is significant air flow. So the bottom water of a koi pond a few feet down would tend to equalize to that temp in the winter except there will be at least a little circulation so it will be lower. Nevertheless the bottom will stabilize significantly warmer than the surface.

However if an especially warm day comes along it will heat the surface water to warmer than the bottom. You can generally tell when that happens as all the fish will come up to the top to be warmer in the sun. However in normal average or usual conditions during winter temperature inversions form and the bottom water is warmer than the top.

These temperature inversions are why pumps and aerators should be turned off in winter as the circulate the water and destroy the temperature inversion making it all colder and worse for the fish.

In winter heaters should be used to keep holes open in the ice to prevent buildup of toxic gases and entry of oxygen into the pond.

Another important Autumn task is the regular (sometimes daily) skimming of fallen leaves from the surface of my ponds with a long net before they have a chance to sink. That's by far the best way. Any excess decaying leaves at the pool bottom need to be removed. This should be done in the fall because their decay over the winter robs the water of oxygen and adds polutants. If a lot do make it to the pool bottom I'd bring out a few scoops a day with a net rather than draining the whole pool. That would stress the fish less and let the sediments settle between times.

I live in the woods also though my immediate yard is fenced again against deer. I feed them just outside. I also have an enormous load of leaves into my ponds in the fall - sometimes on windy days you can't even see the water - but nevertheless I do skim with a net everyday to make sure they don't get a chance to sink to the bottom. I had to get an extension on my big net to reach the center to be able to remove the leaves that way.

Skimmers won't work on heavy leaf loads, that's one reason I don't have one. More trouble cleaning than they are worth. And nets over the pond just get pushed into the water and waterlogged and it's a huge pain taking them on and off. And if you don't remove it you can't feed your fish.

As to cleaning my ponds, I never do that. The natural shallow deposit of muck on the bottom is good and natural as is the algae on the sides which is a source of nutrients for the fish over the winter and throughout the year. And any chemicals going into the pond are bad except in emergencies.

Listening to your fish. If you observe your fish carefully you can often tell by their behavior if anything is wrong before it is too late. Healthy happy fish are full of energy and swim and mingle robustly most of the time in warm weather. Their fins are outstretched and they behave like the rest of their friends.

If they are all hiding they are not happy and something is wrong. I could always tell when a heron had raided my pond because all the fish were cowering at the bottom in the thickest plants.

Unfortunately koi often undergo color changes, often lessening of coloration, as they grow. Even older ones sometimes do. I've had both a 10" and 12" koi lose beautiful red spots entirely. Some types of coloration are more stable than others, such as the all over reflective scale colorations, which I've never seen change much into adulthood, but I've never seen anyone be able to predict color changes in general.

I have one koi I bought because of especially beautiful intense red spots, one a perfect big round circle on the top of his head. I was really disappointed when the circle faded and completely disappeared over a couple months, and the other lost almost all of its red too. Those guys are still around and healthy and I still love them. The one who had the two red spots is really strong. I was trying to net him once and he took off like a shot and shot right out of the pond and over the pavers for about 3 feet, then actually turned around and zipped across the pavers back into the pond. I figured if he put up that much of a fuss I'd better stop trying to net him. He's still robust and happy and no worse for his little escapade.

Normally once color changes it doesn't change back. This is one reason people often prefer to buy fully grown koi rather than small ones, as color changes are less likely.

TWO DIFFICULT ETHICAL QUESTIONS FOR ANIMAL RIGHTS: Is it is better for an animal to have been able to experience a fairly life (assuming either a natural life in the wild or a well treated life on a farm) and then be slaughtered humanely for food, or to have never lived at all? If that animal's life was in fact natural or in pleasant conditions on a farm I would say the former is far preferable than not having the wonderful experience of living a life. However I think there is little doubt that farm animals which live their lives in suffering such as veal calves or factory farmed chickens can not be so justified. Shamefully, billions of animals worldwide live in appaling conditions of incredible suffering all their lives. Just as in Nazi Germany, this holocaust continues largely unseen and all the 'good Germans' cover their eyes and refuse to recognize the truth.

Another important ethical question is whether it is better to kill one 1000 lb cow for food or say 1000 1 lb fish or perhaps 10,000 shrimp weighing 1/10 of a pound? How does one calculate the suffering in such cases? Does one go by the number of deaths or which is the 'higher' species? Certainly all these species experience pain so my inclination is some kind of sliding scale would be most accurate, in other words the deaths of more creatures counts more than their position in the tree of life. In any case it's a difficult question.

ANIMAL RIGHTS ATROCITIES: VEAL: The Veal industry is easily one of the worst offenders. Veal calves are taken almost at birth from their mothers, raised their whole shot lives isolated in pens so small they can hardly move so they cannot exercise so their meat will be tender. They are purposely fed a nutrionally deficient diet which results in severe anemia and other health problems so that their meat is pale and sickly. Why such suffering is tolerated is an indctement of humankind. Do veal eaters even know they are eating extremely sick animals who have suffered all their short miserable lives?

ANIMAL TESTING: Thankfully some progress is being made in replacing live animal product testing with testing in cell cultures but much more remains to be done. In animal testing large numbers of animals (to get a statistically significant sample) are subjected to tortures that would make Dr. Mengele cringe. This is true in cosmetics testing and biological and medical research as well. Much of the reason these atrocities are allowed to contine is that are largely hidden by the media, and those who expose them and attempt to take action to correct them are demonized or ridiculed as 'ecoterrorists'. The fact that the suffering of animals is hidden behind closed doors is an unhealthy relegation of another important aspect of human culture to the unspoken (see the section on this).

The ethics of animal research is a valid subject for an EP debate as it goes right to the heart of the nature of animal mentality and EP ethics. I won't go on at length on this subject but I would point out that insofar as animals are sentient, which they clearly are, any experiment which causes pain, suffering or death to animals becomes questionable, no matter how valuable or interesting the results. There is also the problem of the actual utility of many such experiments which often produce little if any information of value and are driven primarily by a 'publish something no matter how useless or perish' mentality.

Though plenty of valuable information has been derived from properly designed animal experiments it is at the expense of untold suffering of an enormous number of animals which are subjected to experiments that would make Dr. Mengele cringe. And the social mentality which allows the infliction of such suffering predisposes societies to human cruelty as well, or, perhaps even worse, it engenders false rationalizations denigrating the mentality and sentience of animals in an attempt to expunge human guilt. Thus we see the continuous human 'need' to emphasize how humans are 'different' and 'superior' to animals.

George Bernard Shaw put it well when he said something to the effect of 'The knowledge gained from animal experiments is at the expense of human dignity'.

WHY DO WHALES AND DOLPHINS BEACH? The beachings of whales are not completely explained, but I think there is no evidence this is mass or individual suicide as some suggest. Much more likely that they have been affected by either some toxic pollutants or disease organism. Recall that whales must breathe air. It makes sense in times of stress resulting in very low energy that whales would beach so they could attempt to breathe without exertion and rest. This would only be a last desperate measure. Unfortunately they can then be caught as the tide recedes. Thus it is very likely that human attempts to put them back in the water are the worst possible action. Obviously this is exactly what the whales don't want or they wouldn't be on the beach in the first place. The proper human action is to diagnose the problem and attempt to cure it with antibiotics or whatever is appropriate while shielding it from the sun and keeping it wet. Human attempts to aid beached whales are almost always unsuccessful, and are very likely harmful. The whale obviously wants to rest and try to recuperate, however recuperation rarely seems to happen. At least, they should be left to die in peace, or if the problem can be diagnosed, then it should be treated.

In general cetacean buoyancy is so very nearly neutral that it depends on the amount of internal air retained and is under the animal's control. Thus in times of breathing stress they could have problems staying afloat if seriously ill. Here is some data re. sperm whales.

"The model estimated that the density of the non-air portion of all five sperm whales was 1030 kg m-3, or 0.31% denser than seawater at the reference depth of 40 m. Sperm whales killed in whaling operations are typically positively buoyant, but they are reported to sink in rare cases when air is lost due to shooting or a wound (Clarke, 1978c). Although traditional whalers preferred sperm whales because they would float upon death (implying that other whales sink), Berzin (1972) reported that whalers pumped air into sperm whales to keep them from sinking and noted: `At present sperm whales are considered to sink after death, and in fact, some of them do, primarily young animals, that have a smaller amount of fat.' Clarke (1978c) reports a case in which a sinking whale was easily recovered on the line, suggesting only slight negative buoyancy. It therefore appears that at least some sperm whales are negatively buoyant when they have lost their air, in agreement with our findings."

WHY BIRDS FLY INTO WINDOWS: We need to look at windows as birds do to solve the collision problem, which apparently kills millions of birds annually. I'm not sure whether polarization would make any difference or not, most likely the problem is just that the bird sees the trees and sky reflected in the window rather than the window itself. Though to explain why a bird would fly down what would be a visual tunnel through a solid object seems rather strange and implies that birds do fly down very tightly focused visual paths. There seem to be no really effective means of preventing collision other than obscuring windows from the outside. One promising approach is to apply frosted UV reflective coatings on the outside. This might be visibly opaque to the birds but not obscure the view to the human looking out.

Mark Peaty has now suggested what I think is the correct explanation:

"MP: It's not so strange if you think of a house being of similar _size to a tree, or group of trees. Birds around here regularly _fly between foliage laden branches, and between the lowest _branches and the ground. Indeed most of them seem to be adept at _flying *through* trees, or at least that is how it looks from _beside or below their flight path. I think that most birds can _judge whether an air-gap ahead of them through an otherwise _solid object is big enough to accommodate their wing span and _'flapping space'. That being so, the sight of sky or clouds _appearing to be beyond the solid object and apparently _accessible by direct flight through is all they need to choose _that pathway. It seems to me that they usually only veer away _when they are close enough to see their own reflection.__

I think birds choose to fly through such spaces as a matter of _convenience, ie flying up and over a tree or tree like object _takes more energy than maintaining level flight through a _convenient air-gap. Energy efficiency seems to be a very strong _determinant of what birds do, no surprise there of course! _Digression: = The undulating flight of small birds is a _particular example of this: the repeated pattern of fluttering _acceleration and climb followed by a short period of _wings-folded, ballistic 'parabola' reduces drag overall. Any _extra energy expended in the short climb is more than _compensated for in the wingless glide which follows"

ROAD KILL: Another question is why so many animals die killed by vehicles on the roads when they are so adept at avoiding the charge of their natural predators? I think the answer to this is simple. Animals instinctually flee oncoming motion of large objects, but only when such motion is articulated. That is it is the articulated movement of the approaching predator's legs that most animal minds are cued to detect and flee from, rather than the motion of a vehicle which approaches as an unchanging mass. There are no doubt some important additional insights into the animal mind to be discovered here.