You are currently browsing the tag archive for the ‘senses’ tag.

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Pseudoscience, quackery, “magic”, and deceptive supernatural practices meant to defraud people (often including the practitioner…for our need to believe in things is deep and desperate indeed) are as old as humankind, but I doubt that many schools of augury are quite as outwardly preposterous as myomancy, divination by means of rats and mice.

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The Romans were into augury of every sort, but they seem to have had a particular fondness for myomancy, and Pliny the Elder refers to it directly several times in his histories (although, in the end, all that study of rat augury doesn’t seem to have kept him safe from unexpected volcanic eruptions).  Myomancy could be “practiced” by freeing rats or mice and seeing which way they fled, by watching the rodents navigate mazes/pictograms, or by simply observing their lives in the wild.

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This last “wild” myomancy was perhaps the most highly regarded, yet it was also the most rare and spontaneous.  Mice and rats were sometimes thought to scream out before a disaster…or to just run away before a calamity.   If rats suddenly fled a house or community, it was thought to be bad luck of the most astonishing sort. Likewise. if a huge number of rats or mice simply appeared, it betokened a coming war or illness.  If rodents were spotted gnawing clothing (or, worse, armor or military equipment) it was regarded as a sign of incipient defeat.

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Now, animals perhaps don’t have occult connections to the forces of fate and divinity, but they have extreme sensory acuity (or sometimes they have entire senses we lack!).  Modern scientists have noticed that animals, particularly rats and mice, can predict earthquakes or extreme weather events.  Rats and mice are sensitive to air changes which betoken fire, pollution, or anoxygenic conditions.  Additionally, if a bunch of rats suddenly appear seemingly out of nowhere it is a pretty dire sign that something has gone very wrong with some fundamental link in an ecosystem.  Famine or pestilence may indeed be on the way.  The link between rats and bubonic plague is direct and (now) well known.  If rats start stumbling out of the woodwork and dying, collect all of your strongest antibiotics and RUN.

So I started this post by belittling myomancy, which certainly sounds less august than reading the stars or speaking to the dead or what have you.  However, on closer examination, it seems like myomancy might provide some real and useful information, which other schools of augury lack entirely.  This is not because myomancy is magical, but instead because rats and mice are clever and sensitive and must stay hyper-alert to survive in a world of poisons, predators, giants, and catastrophes.  Pliny the Elder was one of the forefathers of the natural sciences–perhaps we can still learn some things from him (see more next week), so keep an eye out for mysterious rodent happenings.  You never know what they will tell you! If Pliny hadn’t gotten distracted by the giant mushroom cloud above Vesuvius, he probably would have noticed rats running the other way as fast as they could.

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11949868721596191242creation_day_5_number_ge_01.svg.hiOf the top ten posts of all time, number five is my personal favorite. As you might imagine, it deals with catfish—those bewhiskered masters of freshwater survival. Catfish live on all continents (other than Antarctica—where they once lived) and they thrive in virtually every freshwater habitat worldwide. The siluriformes have even left freshwater and begun to reconquer the ancient oceans from whence all chordates originally sprang. They are a phenomenally successful family—one of life’s greatest success stories. When Earth life finally leaves home and blasts off into the greater firmament, I am sure catfish will find a way to tag along in our fresh water supply (assuming we can ever look up from our stupid I-phones and celebrity folderol for ten minutes to make such a thing happen).

 

A school of Striped Eel Catfish (Plotosus lineatus)

A school of Striped Eel Catfish (Plotosus lineatus)

Ferrebeekeeper has featured all sorts of catfish posts: catfish in art, the politics of farm-raised catfish, colorful catfish, venomous coral reef catfish, even terrifying underworld gods that are catfish! There are upside-down catfish, and catfish which care, and even wild catfish living in Brooklyn (both at the beach and at the reservoir). Tune in later this autumn when we will go all celebrity chef and cook a delicious catfish! I guess what I am saying is that I really like catfish! I admire their astonishing versatility. The secret to their success is straightforward but hardly simple—they have a vast array of astonishing sense organs which allow them to thrive in environments where other fish are lost. Even if their habitat is dark, turbid, or chaotic—the numerous senses of the catfish (some of which are not possessed by humans) allow it to evade predators, find food, and carry on a social life which is often surprisingly elaborate. You can read all about these astonishing senses in Ferrebeekeeper’s fifth top post of all time “Sensitive Siluriformes: How Catfish Perceive the World.”

 

M. Tigrinus

Merodontotus Tigrinus (The Zebra Shovelnose Catfish)

After you are done reading (or re-reading) the original post, I hope you will pause to reflect on how astonishingly beautiful and sophisticated life is. Most people I talk to initially dismiss catfish as lowly bottom-feeders (or possibly talk about them as delicious sandwiches), but they are magnificent organisms which live everywhere based on senses we are just beginning to understand. They are also related to us: distant cousins who stayed closer to the traditional ways of our great, great, ever-so-great grandparents the ancient lobe-finned fishes of the Silurian. But despite their adherence to a traditional aquatic lifestyle the catfish are hardly unsophisticated cousins!

Grandpa?

Grandpa?

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The Congo River is the world’s second largest river by volume of water discharged (which seems like the most worthwhile measure of a river). Portions of its watershed are both north and south of the equator—which ensures that some part will always be experiencing a rainy season. The Congo River flows through the world’s second largest rainforest, and, as you would expect, the waterway teems with exquisite animals of multitudinous variety. There are aquatic mammals, many different sorts of crocodilians, turtles, frogs, snakes, mollusks, insects, crustaceans, and there are fish fish fish! The piscine variety is staggering: stingrays, carp, cichlids, pufferfish, African tetras, and the highly predatory giant tigerfish. There are also some bizarre blind deep water fish—because the Congo is the world’s deepest river (with depths of at least 220 m (720 ft)).

A few Congo River Fish

A few Congo River Fish

Ferrebeekeeper has always been devoted to catfish which thrive everywhere other than the deep ocean or the arctic. Indeed there are all sorts of catfish in the Congo River—particularly squeakers (AKA upside-down catfish). However, as a special treat, let’s take a break from catfish and talk about an entirely different fish—the freshwater elephant fish (the Mormyridae family from the order Osteoglossiformes). According to the World Wildlife Fund, Elephant fish are the dominant fish fauna in the Congo River. And they are downright strange in so many ways.

Campylomormyrus rhynchophorus

Campylomormyrus rhynchophorus

As you might surmise, elephant fishes earned their common name from their long trunk-like mouths (although this feature is certainly not universal among the 200 plus different varieties). Different species vary greatly in size: the smallest elephant fish are only 5 cm (2 inch) when they reach adulthood whereas the largest grow to 1.9 meters (4.5 feet) in length. Like the electrical catfish and ghost knife fish of the Amazon, the elephant fish have electroreceptive sensory organs. These generate an electrical field and “read” the field so the fish can sense the world (and especially other living things) very clearly even in the murkiest waters and in complete darkness.

 (Image: Carl Hopkin)

(Image: Carl Hopkin)

Elephant fish are extremely intelligent fish with a greatly enlarged cerebellum. In fact the fish have a brain body ratio which is approximately the same as humans (although it seems that they use much of their mental power to operate their electrical sensory organs and interpret the electrical data). In humans, the cerebellum controls movement, motor control, and language so it is speculated that elephant fish may have greater abilities to communicate with each other than we currently understand.

Campylomormyrus alces (from aquaria2.ru)

Campylomormyrus alces (from aquaria2.ru)

Oh, also the elephant fish (and their closest relatives the African knife fish) are unique in that their sperm lack flagellums. Of all vertebrates—from turkey to megabat to axolotl–these strange African fish are the only chordates not to have motile sperm. I wish I could tell you more about that business, but I cannot (and researching it on Google has not made me happier or wiser).

 

Genyomyrus donnyi (George Albert Boulenger)

Genyomyrus donnyi (George Albert Boulenger)

I have tried to show some elephant fish which are endemic to the Congo River, but, alas, I am not an ichthyologist (although that might have been a good career choice) so I may have messed up. Hopefully these photos at least provide some small overview of this incredible family. Humankind needs to learn more about these splendid clever African fish which are so prevalent in the turbid waters of the great tropical river.

Mormyrops anguilloides

Mormyrops anguilloides

Garter Snake Tongue (by kenhipp)

Garter Snake Tongue (by kenhipp)

Snakes might not be out there penning beautiful odes or solving quadratic equations (although they have the intelligence necessary to hunt clever birds and mammals) however the reptiles are distinguished by their amazing sensory abilities.  Like the extraordinary siluriformes (the catfish, which are living tongues that apprehend the world in astonishing ways), certain snakes have abilities to perceive things which other animals simply cannot detect.

Snakes double the primary senses of hearing, smelling, and sight—which means that some snakes effectively have eight or more senses.  Let’s go through these senses individually.

Hearing: Although the reptiles lack external ears, they have sensitive inner ears which allow them to hear airborne vibrations.  This however is only one mechanism of hearing for snakes: the animals have jaws linked to their inner ears which allow them to hear extremely faint vibrations.  Since most serpents have lower jawbones which are separated into two distinct bones, the animals are extremely adept at locating the source of a sound from the different time/frequency that vibrations strike the different bones. This means they can hear the source of sound with pinpoint accuracy.  These hearing abilities give some snakes 9especially desert snakes) the ability to hunt by sound in absolute darkness.

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Smell/taste:  Snakes breathe through two nostrils, but unlike mammals their “noses” have little to do with their sense of smell.  To quote an article involving snake senses from reptilis.net:

…snakes have gone a different route, one taken by their lepidosaurian relatives a long time ago. Instead of using only their nose, snakes have adapted their tongue and sense of taste to capturing scent particles in the air and transforming it into olfactory information.

Better yet, because snakes “smell” by “tasting” the air with their tongues, and because those tongues are typically forked, they also have incredible directional smelling. Snakes effectively smell in stereo.

So snakes are capable of amazing abilities to taste/smell their environment and they have directional smell which almost acts like hearing or sight in locating prey or mates.

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Sight: Most snakes have conventional binocular optical abilities on par with other vertebrates (although tree snakes are known to have particularly fine vision) however many groups of snakes (particularly the python and viper families) possess astonishing heat-sensing pit organs that can detect infrared light.  For their size, the sense organs are more heat sensitive than anything humans have created with technology.

Touch: Snakes have an amazingly sophisticated sense of touch (as one would might imagine for an animal which lives on its belly). Thanks to their sense of touch they can respond immediately to stimuli from their environment and they can feel the slightest changes in their habitat.  Additionally touch is important for snakes socially and is a primary means of communication between snakes of the same species.

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As with sharks, cats, and owls, snakes have used their astonishing senses to become formidable predators.  Snakes are widespread in all of the continents other than Antarctica and they dwell in all habitats other than permanently cold ones and deep ocean (well, plus a couple of weird islands).   This success is a result of their sharp and numerous senses.

The worldwide range of all snakes

The worldwide range of all snakes

Synodontis schoutedeni catfish (Credit: Oliver Drescher)

So what’s so amazing about catfish?  So far, Ferrebeekeeper has describing all sorts of different variations of these fascinating fish. From the giant truck-sized catfish of the Mekong, to the infinitesimal (yet horrifying) candirus of the Amazon, to the deadly poisonous schooling catfish of coral reefs, to catfish that live underground or in gardens, we have seen a seemingly impossible variety of the irrepressible whiskered creatures. But, aside from their variety, hardiness, and interesting appearance, catfish represent an extraordinary apogee in sensory ability.  They are able to apprehend their watery realms in ways that might as well be supernatural or alien to us.  Catfish have honed familiar senses—taste, smell, touch, hearing, and sight–to outrageous extremes. Yet they have additional senses—electroreceptivity, pressure sensitivity, and possibly other senses–that we are only starting to understand.

Channel catfish, Ictalurus punctatus

Let’s start with catfish’s sense of taste: catfish, unlike us, are not limited to tasting things with their tongues.  Their entire bodies are covered with taste buds.  To quote catfish expert Dr. John Caprio of Louisiana State University, “Catfish are swimming tongues…You can’t touch any place on a catfish without touching thousands of taste buds. To use an analogy, it’s as if the tip of your tongue grew out and covered your body.”  Catfish can literally taste the water all around their bodies and the mud they are swimming over.

Red-tailed Catfish, Phractocephalus hemioliopterus (Photo by Chad Cullen)

Beyond their powers of taste, catfish have a bloodhound-like sense of smell. With astonishingly sensitive olfactory pits near their nostrils, Catfish can smell certain compounds at one part per 10 billion parts of water. The sense of smell does not merely help them while hunting and seeking food, catfish use smell to identify other individual catfish and to maintain a social hierarchy.  A catfish has an elaborate picture of its watery realm, the denizens thereof, and of the history and interaction of these inhabitants based on smell.

Catfish Barbels

Catfish’s scale-free skin is unusually sensitive to touch but that is not the end of catfish’s ability to feel what is going on around it.  The most distinctive feature of catfish—their 8 barbels (whiskers) are literally organs for touching.  Like a blind man’s cane, each of these barbels can touch the substrate or whatever is moving in front of the catfish.  Not only are the barbels covered with taste buds and feeling nerves, the whiskers also vibrate with water disturbance and provide a sense almost like hearing—although catfish also have multiple hearing organs.

Black Bullhead Catfish (notice the prominent lateral line)

Vibrations travel well under water and most fish have excellent abilities to sense sound, but catfish have evolved some additional auditory features.  The swim bladder of a catfish (which the fish uses like a submarine ballast in order to rise and fall through the water column) is connected by a series of small bones (the Weberian apparatus) to the hearing apparatus (otoliths) inside the head. Catfish are therefore able to hear sounds of a higher frequency than other freshwater fish.  Catfish can also sense extremely low-frequency sounds thanks to a different hearing system—a series of small pores running along the fish’s lateral lines. Within the pores are infinitesimal hair-like sensing apparatuses which respond to the slightest water displacement. Using lateral line hearing, a Catfish can sense animals scuttling across the rocks on the bottom of a river, predators swimming above them, and even fishermen walking on the shore. Perhaps most remarkably, the low frequency sensors which catfish have in their lateral lines seem to give the fish the ability to detect seismic activity.  The Chinese and Japanese are said to have used the creatures as advanced earthquake detectors (which probably gave rise to the myth of Namazu, the Japanese earthquake catfish).

Although some catfish have small or underdeveloped eyes, the majority of catfish species can see extremely well. Additionally catfish possess a tapetum lucidum—a layer of reflective tissue at the back of the eyes which allows them to see keenly in low-light conditions (cat owners will recognize the tapetum lucidum as the flashing green glow of feline eyes).

Catfish in an Aquarium (further documentation required)

Finally catfish can sense the electrical discharges within the nervous and electrical-muscular systems of living things (in fact the electrical catfish goes a step beyond and uses electricity for hunting and self-defense).  The cells responsible for electroreception are found grouped together in tiny pits along the catfish’s head and along its lateral line.  Although electroreception has limited range, it is a powerful sense which can allow the fish to sense animals hidden beneath the mud or otherwise camouflaged.

A catfish’s life must be exciting—awash as they are in complicated overlaying sensory perceptions.  Their abilities to perceive the world have taken them farther than other fish. According to the Tree of Life web project:

Catfishes are a species rich and exceptionally diverse group of fishes ranking second or third among orders of vertebrates. The Catalog of Fishes (Eschmeyer, 1998 et seq.) database treats 2,855 species of catfishes as valid. About 1 in 4 valid species of freshwater fishes, 1 in 10 fishes, and 1 in 20 vertebrates, is a catfish.

Several hundred more species of catfish have been discovered since the above paragraph was written.  Paleontologists have even discovered fossils of catfish on Antarctica (the only continent where they can not currently be found living). Catfish are basically sentient sense-organs.  They have diversified and thrived by being able to discern what is going on in the world around them (and they have probably enjoyed the experience).

Ancistrus Bristelnose Catfish

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