10 Radically Different Ways Animals See the World


Contrary to popular (and typically arrogant) belief, many animals see the world at least as well as–and very often better than–us humans. Of course, ?reality? is always subjective; but as far as sensory input goes, our image of the world is actually far ?less complete? than many animals we see as subordinate.

Below are 10 radically different ways that other Earthlings see the Earth.

10. Giant clams live in a world of colorful blobs

You might not have seen them, but snails actually do have eyes–one on each of their upper tentacles or ?antennae.? They use these to make out forms from a short distance away, then, as they get up close, they?ll reach out with their ?feelers? (the short lower tentacles) to learn more about what they?ve discovered. In fact, sight is so important for getting around that snails actually have light-sensitive cells all over their bodies, allowing them to ?see? shadows falling from virtually any angle.

Adult giant clams, another type of mollusk, are by contrast completely immobile. So we might expect them to see nothing at all. As it turns out, however, they?re equipped with hundreds of tiny ?pinhole? eyes: cup-like cavities with narrow, lensless apertures. They?re unable to identify forms, but giant clams have an interesting advantage over snails: they appear to have color vision. We can only imagine what they see in their 100+ years underwater, but researchers think it may be a panoply of psychedelic lights–colorful blobs indicating potentially predatory movement and warning the clam to squirt water in defense.

9. Sharks see more than we think

It?s long been assumed that sharks have poor eyesight–but only because their other senses are so good. They can, for instance, detect subtle chemical changes (equivalent to a single drop of blood in a million drops of water), and hear very low-frequency (infrasonic) sounds, such as from wounded fish. They also have extraordinarily sophisticated pressure sensors–essentially pores that map their surroundings. And they can even sense electric fields, possibly allowing them to migrate based on geomagnetic field lines, and certainly allowing them to sense bioelectrical signals from their prey.

As it turns out, however, their eyesight is top-notch too; it just isn?t as important a sense. Not only can sharks see in almost all directions at once (thanks to the placement of their eyes on their heads), they can also see up to 10 times better than us in clear water. Dark or murky water isn?t a problem, either; they still see pretty well, even without taking the other senses into account–all of which combines to make sharks such effective predators.

8. Jumping spiders see better than us

Despite having up to eight eyes, most spiders don?t see very well. Often, they?re only really able to tell the difference between light and dark, relying instead on touch (e.g. vibrations) and taste to get around. Even those that can (presumably) make out forms are thought to see only low-res impressions of what they?re looking at because of the ?relatively coarse-grained mosaics of receptor cells? that make up their retinas.

But there is at least one notable exception: the jumping spider. Not only does it see in high-resolution–through its largest, forward-facing pair of eyes (the others being for peripheral vision and motion detection)–but it can actually see more colors than we can, including those in the ultraviolet range.

They also appear to have some intelligence traits of larger animals, such as forward planning and abstract thinking–both of which are important for a predator that preys on other predators. Specifically, jumping spiders are able to visualize and retain a mental image of where their prey might be hiding to plan out a route and surprise it. Rather unnervingly, researchers testing this ability were careful to keep themselves hidden from the arachnids because, as they noted, jumping spiders are attracted to blinking.

7. Vipers, pythons, and boas see heat

Snakes are generally thought to see combinations of just two colors–green and blue–although some nocturnal/crepuscular species also see ultraviolet. Species that hunt during the day, however, often filter blue and ultraviolet light out–a little like they?re wearing sunglasses–which is why their eyes can appear yellow. Either way, with the possible exception of the cobra (which can accurately target our eyes with its venom right out of the shell), snake vision is thought to be blurry.

To compensate for this, many snakes–especially the nocturnal species–are able to ?see? infrared. Humans and other animals can perceive this range of the spectrum, but most of the time only as heat. By contrast, snakes may actually render mental images of their surroundings based on infrared radiation–heat signatures, in other words, of hazards and prey. Vipers, pythons, and boas receive these signals from up to a meter away through their ?pit organs?–holes between the nostrils and eyes activated by temperatures over 28 ?C.

Needless to say, a snake?s eye view of the world is worlds apart from the one that we know, and it?s easy to see why they?re so good at hunting. In fact, this natural infrared detection is thought to be the best on the planet–far better than even our most advanced technological imitations.

6. Box jellyfish see all

Most jellyfish have pretty basic vision, usually limited to light-sensitive cells that help orient them relative to the sky. The box jellyfish, however, has 24 eyes, each serving one of four different purposes (and brains) to give an unprecedented, 360? view of its world. This is perhaps unfortunate for other species given its reputation as ?the world?s most venomous creature.?

One set of eyes detects obstacles, helping box jellies to swim as well as they do, making rapid 180? turns as they traverse the ocean floor. Other eyes detect the visual properties of whatever they meet. While most of these eyes hang at varying levels from the body, four are constantly fixed not just upward but actually at a point beyond the water?s surface–such as the canopy of their mangrove swamp habitats, some eight or more meters above them. No matter which way the jellyfish is ?facing,? crystal-weighted stalks ensure these four eyes always look up–vital for navigating to and from their homes among the mangrove roots.

5. Bees see hidden patterns in petals

There are many remarkable things about bees, not least about their vision in particular. For one thing, they navigate based on the position of the sun without actually having to see it. As long as there?s sunlight getting through the clouds, even on an overcast day, bees are able to compute a homing vector by the distance flown in each direction relative to the layout of polarized rays (effectively vertical pillars of light). This allows them to cover great distances and always return to their hives. And when they get there, they might communicate the route they took by way of their famous ?waggle dance.?

Bees can also see in color–which might be surprising at first, until you consider that flowers evolved to be as attractive as possible to their pollinators. In fact, bees are privy to a beauty in flowers that humans are unable to see. Like us, they perceive three basic colors; but instead of red, green, and blue, they see blue, green, and ultraviolet, allowing them to see striking UV patterns on petals. These patterns evolved to help bees find the nectar right away and might therefore be arranged as targets in concentric circles or as precisely placed dots telling the bee where to stick its tongue.

Bees actually have five eyes: three simple ones, or ocelli, on the top of their heads, and two larger eyes–each with many thousands of lenses (or ?facets?, like impossibly priceless gems)–on the sides. As a result of their excellent vision, bees? color perception is the fastest of any species on the planet, and they can easily distinguish between individual flowers in a group no matter how tightly they?re packed in together.

So much for the so-called ?humble-bee?; this animal?s cutting-edge evolutionary supremacy reflects its central importance to the wellbeing of so many others.

4. Migratory birds see the planet’s magnetic field

Birds can see ultraviolet too, but not at the expense of red light. Whereas humans have just three types of cone cell, allowing us to see the world in red, green, and blue, a lot of birds have four types: red, green, blue, and ultraviolet. As tetrachromats, they see up to 99 million more colors than we can, and, thanks to a special oil drop filter in each cone cell, they?re much faster at distinguishing between them. Naturally, this helps birds forage for seeds, berries, fruits, and insects. It also helps some birds, like the vole-hunting European kestrel, to spot UV reflections from urine trails.

But superior color perception is far from the extent of their prowess; many birds also see the planet?s magnetic field. Based on studies of robins and zebra finches, researchers believe that cryptochromes (a class of blue-light-sensitive eye proteins) convey a sense of magnetoreception to these and other migratory birds. It?s unknown how exactly the magnetic field appears, but it may be as a band of light or blue trail–a kind of filter on their regular vision that helps them to navigate the globe.

3. Donkeys have almost 360-degree vision

While ?ambush predators? like cats, foxes, and crocodiles (i.e. those that stalk their prey and strike at close range as opposed to chasing it down) tend to have vertical slit pupils, grazing prey animals like donkeys, horses, goats, and sheep have horizontal slits instead. Vertical slits help judge distance with minimal maneuvering of the head, whereas horizontal slits receive light from a much wider field of view–allowing grazers to see (almost) all the way around them at once, or up to 350?. Humans, meanwhile, are forced to make do with 120?.

To put this in perspective, imagine you?re a beach donkey (which happens to be a thing in Britain) facing out to sea. With a 350? field of vision from the eyes on the sides of your head, you?d be able to see not only to the horizon ahead of you, but right the way along the beach to either side and much of the inland scene behind you. Your only blind spots would be two rather negligible zones directly in front of and behind your head. Furthermore, as you tilt your head to the ground, your view would remain much the same thanks to a mutation called cyclovergence–the rotation of your eyes in their sockets to keep your pupils forever parallel to the ground.

Needless to say, horizontal pupils help to spot predators in the wild. Indeed, they?re so useful for prey animals that they evolved independently in a number of unrelated species, including mongooses, flying frogs, and octopi.

Our circular pupils, meanwhile, help us to see detail in bright light, which comes in handy for foraging (as well as for using computers) and explains why squirrels and birds have them too. But they also help with chasing down (as opposed to stalking) prey, which is why they?re found in dogs as well. Cuttlefish, incidentally, have W-shaped pupils, which are thought to balance vertically uneven light fields in their habitat.

2. Bats and dolphins see sound

Bats are popularly thought to be blind, but actually they see quite well. In low-light conditions, such as at dawn or dusk, they may even see better than us. It?s just that echolocation is more important for hunting. Bouncing high-frequency shrieks off their surroundings and prey, bats analyze echos within milliseconds, gauging the timing, direction, and frequency of return signals to map their environment in detail and pounce on their prey with precision.

Although echolocating ?microbats? do not rely on their eyes as much as non-echolocating ?megabats? (e.g. fruit bats and flying foxes), they do nevertheless use them for social interaction, to watch for predators, and to assist with navigation. Actually, since their echolocation range is approximately 33-66 feet, they need their eyes to see anything outside of that.

Dolphins use echolocation too, of course. And, because sound travels faster in water, they?re thought to be more efficient than bats. Some researchers even believe that dolphins use echolocation to communicate in a ?sono-pictorial? form of language–the exchange of ?holographic acoustic images? (as opposed to merely symbolic sounds) to refer to objects, places, and perhaps even abstract ideas.

1. Time is completely relative

It?s common knowledge that animal lifespans vary, but so does their perception of time. It all depends on how quickly they process sensory input. Researchers tested this by flashing a light at different frequencies and measuring different animals? brain activity with electrodes. Some animals were capable of seeing the light blink on and off at frequencies so high that humans only see it as constant. In other words, these animals see the world in what we would call slow motion, or even ?bullet time.? This is important for both predators and prey in the wild but, crucially, it?s not a trick they deploy on command before returning to time as we know it; rather, time actually passes at a different rate, and no rate is any less valid than another.

The implications of this are very interesting. Dogs, for instance, take in visual information 25% faster than humans, which makes television appear as a series of flickering images. Flies take in visual information a whopping 400% faster, which is why they find it so easy to avoid being swatted; as far as they?re concerned, the swatter comes down at a snail?s pace (or at least a snail?s pace as it appears to us humans).

Generally speaking, the smaller an animal is, the faster its metabolism and the slower time passes (at least relative to some imaginary constant). Interestingly, this appears to hold true even for animals of the same species, such as children and adult humans. Ever wondered why time goes so much quicker as you age? Well, now you know!

Liked it? Take a second to support Toptenz.net on Patreon!

Leave A Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.