Whale's eye

In Beautiful Whale, [Bryant] Austin describes an encounter with Ella, a curious minke whale off the coast of Australia. He was taking photographs as Ella swam around. The whale liked to look at him head on, a fact that Austin used to maneuver her into better lighting. Her desire to see his face was strong enough that she'd swim around him, if he turned his back to her.

"This requires some discipline and trust in the whales. At times Ella would initiate a close inspection of me from behind, where ambient lighting was poor. Peering over my shoulder, I could see her body pass by less than six feet away. I turned back to face forward, trusting her not to accidentally harm me," Austin writes. "In my experience working with whales this way, our eyes seem to gravitate toward each other." 

-- Alexis Madrigal

Living colour

A previous post refers the extraordinary colour vision of Gonodactylus and other stomatopods. (If you haven't already listened to Radiolab's singing a rainbow podcast, do). But closer to home than this strange undersea creature there are creatures whose colour vision is amazingly refined compared to ours (though less refined than that of stomatopods): songbirds.

In The Forest Unseen David George Haskell describes vision in the chickadee:

Chickadee eyes...perceive more colors than mine can. I view the [ground] with eyes that are equipped with three types of color receptor, giving me three primary colors and four main combinations of primary colors. Chickadees have an extra color receptor that detects ultraviolet light. This gives them four primary colors and eleven main combinations, expanding the range of color vision beyond what humans can experience or even imagine. Bird color receptors are also equipped with tinted oil droplets that act as light filters, allowing only a narrow range of colors to stimulate each receptor. This increases the precision of color vision. We lack these filters, so even with the range of light visible to humans, birds are better able to discriminate subtle differences in color.  Chickadees live in a hyperreality of color that is inaccessible to our dull eyes.

It may be possible one day, far in the future,  to engineer something like this in humans. At present hallucinogenic drugs offer an impression or illusion that we can perceive colours far beyond the normal realm of experience.  Oliver Sacks [1] reproduces this account from a young man who was a subject in an LSD study at Columbia University in the 1950s or 60s:

The room about me receded into a tunnel of oblivion as I vanished into another world...The heavens above me, a night sky spangled with eyes of flame, dissolve into the most overpowering array of colors I have ever seen or imagined, many of the colors are entirely new -- areas of the spectrum which I seem hitherto to have overlooked. The colors do not stand still, but move and flow in every direction, my field of vision a mosaic of unbelievable complexity.

Sacks reports that a combination of amphetamine, LSD and cannabis allowed him to experience a pure indigo:

It was the color of heaven, the color, I thought, which Giotto had spent a lifetime trying to get but never achieved -- never achieved, perhaps, because the colour of heaven is not to be seen on earth. But it had existed once, I thought -- it was the color of the Paleozoic sea, the color the ocean used to be. I leaned toward it in a sort of ecstasy. And then suddenly it disappeared, leaving me with an overwhelming sense of loss and sadness that it had been snatched away. But I consoled myself: Yes, indigo exists, and it can be conjured up by the brain.

A few months later Sacks briefly experienced 'indigo' again with the aid not of drugs but the music of Monterverdi.

But by whatever means humans induce new experiences of colour in future, there will be a foundational difference between those experiences and the experiences of birds and stomatopods. In the case of the latter two, the capability is an advantage in the pursuit of prey, and has been naturally selected.

Footnote

[1] Hallucinations (2012) by Oliver Sacks quoting from The Drug Experience (1961) by David Ebin.

Seeing as if for the first time

'Tis not unlikely, but that there may be yet invented several other helps for the eye, as much exceeding those already found, as those do the bare eye, such as by which we may perhaps be able to discover living Creatures in the Moon, or other Planets, the figures of the compounding Particles of matter, and the particular Schematisms and Textures of Bodies.

-- from the Preface to Micrographia by Robert Hooke (1665)  

The image shows spherical colonies of Nostoc commune, a bluegreen alga. A darkfield illumination by Gerd Guenther. It is one of the prize winners in the Olympus BioScapes Digital Imaging Competition.

The eyes of Anomalocaris

...this magnificent animal, probably the first in the line of apex predators of these shallow seas, had a compound eye that, in many ways, resembled the eye of today’s dragonfly. Anomalocaris had perhaps as many as 16,000 hexagonal facets (individual units of the eye called ommatidia) in each eye and probably good vision.

--Ivan R Schwab

The Gorgon Stare

Just in time for the spring offensives in Afghanistan and Pakistan, the Air Force should deliver the marvelously named Gorgon Stare sensor.

The first three Gorgon Stare pods, mounted on Reaper MQ-​​9s, will make to Afghanistan around March or April... Gorgon Stare uses five electro-​​optical and four infrared cameras to take pictures from different angles. Those are put together to build a larger picture. That provides more detail and more flexibility than the current cameras, but perhaps its biggest advantage will be the ability to provide 10 video images to 10 different operators at the same time.

--DoD Buzz via TomDispatch

Cubozoa

"These eyes have some very peculiar features, and show that once again nature trumps the imaginations of science fiction artists," says P Z Myers.

"These are fantastic creatures with 24 eyes, four parallel brains and 60 arseholes," says Dan Nilsson.

Image from here.

Seeing the light

Last year, scientists discovered that [Mantis shrimps] can...see circularly polarised light, which travels in the shape of a helix. To date, they are still the only animal that can see these spiralling beams of light.

The secret lies at a microscopic level. Each eye is packed with light-sensitive cells called rhabdoms that are arranged in groups of eight. Seven sit in a cylinder and each has a tiny slit that polarised light can pass through if it's vibrating in the right plane. The eighth cell sits on top and its slit is angled at 45 degrees to the seven below it. It's this cell that converts circularly polarised light into its linear version.

In technical terms, the eighth cell is a "quarter-wave plate", because it rotates the plane in which light vibrates. Similar devices are also found in camera filters, CD players and DVD players but these man-made versions are far inferior to the mantis shrimp's biological tech.

-- Ed Yong reports on a paper by N.W. Roberts et al.

By contrast some of the simplest known eyes consist of only two cells.

Blindsight and beyond

The neuropsychologist Stephen Kosslyn has commented, in relation to metamorphopsia: "[The] dissociation between experience and function is fascinating, suggesting that experience is produced by a collateral process...outside the 'chain of command' that results in recognition. If so, then this collateral path can be disrupted while the main one is left unimpaired."

Kosslyn's suggestion is, I think, right on. The only reasonable inference is that sensation (which is clearly what he means here by "experience") is indeed "outside the chain of command" that leads to perceptual recognition. However, [no one who has] thought about these strange phenomena [has] as yet been ready to follow where, to me, they seem obviously to lead.

If sensation can be side-lined, then doesn't this mean that sensation is in reality some kind of side show? It might be going too far to suggest that sensation plays no part in perception. But I think the weight of evidence really does suggest that sensation and perception, although they are triggered by the same event, are essentially independent takes on this event, occurring not in series but in parallel, and only interacting, if they ever do, much further down the line.

-- Nicholas Humphrey (2006)


Photo: Peek-A-Boo Slot 1, Grand Staircase-Escalante, Utah.

Presence

The presence of mental images and their use by an animal to regulate its behavior, provides a pragmatic working definition of consciousness.

from D.R.Griffin on The Question of Animal Awareness (1976) - one of many definitions of consciousness


Phidippus mystaceus (a jumping spider)

Dancing

New Scientist reports that 'dancing' Volvox algae can 'waltz' and 'minuet'. [1]



It's another reminder that while green, red and brown algae are often called 'plants', some of them have properties that are almost 'animal'-like. [2] Some dinoflagellates, for example, have simple eyes to hunt for food. [3]

And at a macro scale, kelp (which are brown algae) do remarkable things, as Charles Darwin saw:

The number of living creatures of all Orders, whose existence intimately depends on the kelp is wonderful.

A great volume might be written, describing the inhabitants of one of these beds of seaweed….I can only compare these great aquatic forests of the southern hemisphere, with the terrestrial ones in the inter-tropical regions. Yet if in any country a forest was destroyed, I do not believe nearly so many species of animals would perish as would from here, from the destruction of the kelp. [4]

[1] Dancing Volvox: Hydrodynamic Bound States of Swimming Algae by Knut Drescher, Kyriacos C. Leptos, Idan Tuval, Takuji Ishikawa, Timothy J. Pedley and Raymond E. Goldstein (pdf).

[2] Other 'simple' protists such as forams display remarkable properties too. Lynn Margulis is a microbiological William Blake in her vision of these creatures:

Large single-celled forams choose from brightly colored sand grains the correct ones with which to make shells. Aware of shape and color, they make choices and reproduce their kind. Awareness in some form has been naturally selected for at least 550 million years. For me, our spirituality and moral nature help perpetuate our living communities, just as similar attributes aided previous living communities whose evolution is chronicled in the fossil record.

[3] "By most definitions...the planktonic dinoflagellate, Erythropsidium, must have among the smallest of eyes, since the creature is only 50–70 μm in diameter." -- from You are what you eat by I R Shwab. Others with eyes include: Peridinium foliaceum and P. balticum. See Ultrastructure of Microalgae: nonphotosynthetic plastids.

[4] The Voyage of Beagle, Chapter 11:

Almost all the leaves, excepting those that float on the surface, are so thickly incrusted with corallines as to be of a white colour. We find exquisitely delicate structures, some inhabited by simple hydra-like polypi, others by more organised kinds, and beautiful compound Ascidiæ. On the leaves, also, various patelliform shells, Trochi, uncovered molluscs, and some bivalves are attached. Innumerable crustacea frequent every part of the plant. On shaking the great entangled roots, a pile of small fish, shells, cuttlefish, crabs of all orders, sea-eggs, starfish, beautiful Holothuriæ, Planariæ, and crawling nereidous animals of a multitude of forms, all fall out together. Often as I recurred to a branch of the kelp, I never failed to discover animals of new and curious structures.

Darwin was writing about kelp in cool southern waters. But kelp 'forests' have recently been discovered in deep tropical waters too. It's thought that these may act as refugia under some conditions of climate change.

Seeing

Consider the Mantis shrimp, or Stomatopod, which has the most complex eyes in the animal kingdom, with hyperspectral colour vision allowing up to 12 colour (or perhaps 16) channels extending into ultraviolet, advanced depth perception, and an extensive ability to see polarized light. Intriguingly, these animals have little in the way of brains as we think of them.


Consider, too, a kind of seeing known only by Man: the Earth from space. James Lovelock, the man who imagined Gaia, writes:

The icon is undergoing a subtle change as the white ice fades away, the green of forests and grasslands fades into the dun of desert, and oceans loose their blue-green hue and turn a purer, swimming-pool shade of blue as they too become desert. [1]

Footnote

[1] The Vanishing Face of Gaia (2009). But surely the book is mis-titled; the face of Gaia is changing, not vanishing.

Red underwater

Red light, whatever its source, doesn't travel far through water, which suggests these communications are intended to be private, seen only by nearby fish of the right species. There are several lines of evidence to support this, says [Nico Michiels of the University of Tübingen Michiels]. "Most of these fish are small and live at the bottom in pairs or groups. They are generally quite cryptic but often have conspicuous behaviours characteristic of the species. And there's obvious variation in markings between closely related species, which suggests they might be important in species recognition."

It all sounds very plausible. "The idea of red-light private communication channels is intriguing," says Julian Partridge, head of the Ecology of Vision group at the University of Bristol, UK. He says that if a fish can signal important things without being noticed, there can be big pay-offs. "Long-wave light doesn't travel far under water, so a male fish can wave its red sexy bits at a female and not be noticed by animals further away. Not only will that reduce his chances of being eaten while distracted with flirtation, but it will also make him less likely to be beaten up by a rival."

Michiels suspects that red fluorescence has another important role for some reef fish: helping them blend in with their background rather than making themselves seen. During his first dive with the red filter over his mask, he noticed that reef corals and algae glow a dark but faint red too, with brighter patches here and there. Against this irregular red background, a fish that glows red all over, like the small wrasse, would be hard to spot.

-- from Code red: How deep reef fish keep in touch

Once was blind

This clip is not new, but it is good to be reminded of it.

Beyond strange

A fuller explanation from MBARI. (Hat tip Deep Sea News)

Also in the news: it looks as if the elephant shark, which evolved about 450 million years ago, may be the oldest vertebrate to have "the colour vision system we know as humans".

Essai sur la logique de l'imaginaire

I am studying octopuses at the moment, and that means also learning about their cousins, including cuttlefish. This is Pfeffer's Flamboyant Cuttlefish.

I knew before that cephalapods cannot see colours (although they can perceive polarized light), but I did not know that the lenses of their eyes are "pulled around by reshaping the entire eye" in order to change focus.

(This post is headed with the subtitle of the book on the octopus by Roger Caillois)

Eyeborg

Rob Spence, a 36-year-old Canadian filmmaker, is not content with having one blind eye. He wants a wireless video camera inside his prosthetic, giving him the ability to make movies wherever he is, all the time, just by looking around. "If you lose your eye and have a hole in your head, then why not stick a camera in there?" he asks.

-- Wired

Image: scallop

The eye

From this:

The origin of a light sensitive nerve was almost certainly an early step in the evolution of animal eyes, and this was thought to have happened only once, some 600 million years ago...[1]

To this:

...The eyes of a peregrine weigh approximately one ounce each; they are larger and heavier than human eyes. If our eyes were in the same proportion to our bodies as the peregrine's are to his, a twelve stone man would have eyes three inches across, weighing four pounds. The whole retina of a hawks eye records a resolution of distant objects that is twice as acute as that of the human retina. Where the lateral and binocular visions focus, there are deep pitted foveal areas; their numerous cells record a resolution eight times as great as ours. This means that a hawk, endlessly scanning the landscape with small movements of his head, will pick up any point of movement; by focussing upon it he can immediately make it flare up into larger, clearer view...

...Like the seafarer, the peregrine lives in a pouring-away world of no attachment, a world of wakes and tilting, of sinking planes of land and water. We who are anchored and earthbound cannot envisage this freedom of the eye. The peregrine sees and remembers patterns we do not know exist: the neat squares of orchard and woodland, the endlessly varying quadrilateral shapes of fields. He finds his way across the land by a succession of remembered symmetries. But what does he understand?...[2]

Also, there are humans:

Another thing I have been practicing is wearing the wrong glasses. Now that I have three (or is it five?) different pairs, one for each and every focal distance, I almost always find that I am wearing the wrong glasses for whatever I think I am doing at any given time. This gives me countless opportunities to enjoy a psychedelic blur of the kind we used to seek in the 60s by chemical means, while walking into walls or stepping on my cat Hodge. [3]

Footnotes:

1. From Evolutionary origins of a light sensitive nerve

2. From The Peregrine by J A Baker (1967) -- see also Robert Macfarlane's essay. [Another sensibility at the Derby Cathedral Peregrine Project ]

3. From RALPH.

Seek and hide

Chameleons, it's reported, can fine-tune their colour changes to hide according the visual systems of specific predators. In the presence of a snake, it seems, they don't have to try as hard as they do with birds, which have better vision.

The findings are published not too long after work indicating that chameleons first evolved the capacity to change colours in order to attract the attention of other chameleons.

At least as astonishing are cuttlefish, of whom Les Murray writes:

Spacefarers past living planetfall
on our ever-dive in bloom crystal:
when about our self kin selves appear,
slowing, rubber to pulp, we slack from spear,
flower anemone, re-clasp and hang, welling
while the design of play is jelling,

then enfolding space, jet
every way to posit some essential set
of life-streaks in the placeless,
or we commune parallel, rouge to cerulean
as odd proposals of shape and zip floresce
– till jig-maw apparition
spurts us apart into vague as our colours shrink,
leaving, of our culture, an ectoplasm of ink.