Information

Can platypuses communicate via electroreception?


I know at least some electroreceptive fish are capable of basic communication with other members of their species via varying their own bioelectric signals. However, I can't find any information as to whether platypuses (or, for that matter, any of the handful of other electroreceptive mammals) are capable of communicating in a similar manner. Does anyone know if they're able to do this?


Electrocommunication is used by weakly electric fish only and it is limited to aquatic environments where the electrical conductivity of the medium allows to transmit electric signals. The best studied fish species that use this communication method are The African Mormyriformes (which comprise the Mormyridae or elephantfish and the Gymnarchidae with Gymnarchus niloticus as the only species) and the South American Gymnotiformes (or Neotropical knifefish).[1]

The mammals that are capable of electroreception use it for passive electrolocation which means locating the prey by detecting the weak electric fields of the prey with electroreceptors. These mammals are the three living species of monotreme; the Australian duck-billed platypus (Ornithorhynchus anatinus), the Australian short-beaked echidna (Tachyglossus aculeatus) and the Western long-beaked echidna (Zaglossus bruijnii) of New Guinea; and more recently discovered, the Guiana dolphin (Sotalia guianensis) from the cetacean order.[2][3]

Note: Electroreception was reported in star-nosed mole, Condylura cristata, based on limited behavioral data (Gould et al., 1993) but the theory remains unexplained physiologically.[4]

The electrosensory system of platypus (and probably other mammals) is evolved independently and the electroreceptors belong to the trigeminal system. The physiology of the electosensory system of mammals reveal why they can't use their electroreception for conspecific communication.

In African mormyriform and South American gymnotiform fishes this sense has evolved to an additional active system using an electric organ as a source for a.c. impedance measurement of the environment and for communication. All electroreceptors found in fishes and amphibians that do not have electric organs are of the ampullary receptor type and probably form part of the acoustico-lateralis system. In contrast, the electroreceptors in platypus belong to the trigeminal system. Their sensitivity to d.c. as well as to high-frequency pulses [2] contrasts with the mostly d.c. or lowfrequency responsiveness of ampullary receptors, which are less well-adapted to detect rapid muscle action potentials.

Langner, Gerald & Scheich, Henning. (2009). Electric Senses in Monotremes: Electroreception and Electrolocation in the Platypus and the Echidna. 1056-1060. 10.1007/978-3-540-29678-2_2919.
https://www.researchgate.net/publication/299656487_Electric_Senses_in_Monotremes_Electroreception_and_Electrolocation_in_the_Platypus_and_the_Echidna


References:

1. Map of Life - "Electrolocation and electrocommunication in weakly electric fish" http://www.mapoflife.org/topics/topic_578_electrolocation-and-electrocommunication-in-weakly-electric-fish/
January 24, 2018

2. Passive electroreception in aquatic mammals.
Czech-Damal NU, Dehnhardt G, Manger P, Hanke W.
https://www.ncbi.nlm.nih.gov/pubmed/23187861

3. Electroreception in the Guiana dolphin (Sotalia guianensis)
Nicole U. Czech-Damal, Alexander Liebschner, Lars Miersch, Gertrud Klauer, Frederike D. Hanke, Christopher Marshall, Guido Dehnhardt, and Wolf Hanke
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3248726/

4. Edwin Gould, William McShea, Theodore Grand; Function of the Star in the Star-Nosed Mole, Condylura cristata, Journal of Mammalogy, Volume 74, Issue 1, 19 February 1993, Pages 108-116, https://doi.org/10.2307/1381909


Further reading:

1. Electroreception (edited by Theodore Holmes Bullock, Carl D. Hopkins, Richard R. Fay)

2. Neurobiology of Monotremes: Brain Evolution in Our Distant Mammalian Cousins (edited by Ken Ashwell)

3. Sensory receptors in monotremes ( Proske U, Gregory JE, Iggo A.) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1692308/

4. Electroreception in monotremes (John D. Pettigrew)
https://jeb.biologists.org:2083/content/jexbio/202/10/1447.full.pdf

5. Perceiving in Depth, Volume 3: Other Mechanisms of Depth Perception (By Ian P. Howard)

6. Electroreception and Electrogenesis (James S. Albert and William G.R. Crampton) http://www.ucs.louisiana.edu/~jxa4003/Albert%20PDF%27s/Albert-Crampton-Electroreception-proofs.pdf


Electroreception

Introduction

Electroreception is an ancient sensory modality, having evolved more than 500 Ma, and has been lost and subsequently ‘reevolved’ a number of times in various vertebrate and invertebrate groups. The multiple and independent evolution of electroreception emphasizes the importance of this sense in a variety of animal behaviors from different habitats, including prey detection, orientation, navigation, and the use of bioelectric stimuli in social interactions. The detection of weak electric fields has probably occurred via two different mechanisms: the induction of electrical signals in specialized receptor cells and the interactions of magnetite crystals with the earth’s geomagnetic field . This brief account predominantly concentrates on passive electroreception, where the weak electric fields produced by other organisms or anthropogenic sources are detected using specialized end organs. However, some mention will also be made of the use of geomagnetic cues in navigation and orientation and the subsequent induction of electric fields in some animals. Active electroreception and electrocommunication, which utilizes self-generated signals to navigate through electrosensory space, will be examined elsewhere in this volume.


Anatomy & Biology

The body and the broad, flat tail of the platypus are covered with dense, brown fur that traps a layer of insulating air to keep the animal warm. The fur is waterproof, and the texture is akin to that of a mole. The platypus uses its tail for storage of fat reserves (an adaptation also found in animals such as the Tasmania devil and fat-tailed sheep). It has webbed feet and a large, rubbery snout these features appear closer to those of a duck than to those of any known mammal. The webbing is more significant on the front feet and is folded back when walking on land Unlike a bird’s beak (in which the upper and lower parts separate to reveal the mouth), the snout of the platypus is a sensory organ with the mouth on the underside. The nostrils are located on the dorsal surface of the snout, while the eyes and ears are located in a groove set just back from it this groove is closed when swimming. Platypuses have been heard to emit a low growl when disturbed and a range of other vocalizations have been reported in captive specimens.

Weight varies considerably from 0.7 to 2.4 kg (1.5 to 5.3 lb), with males being larger than females males average 50 cm (20 in) in total length, while females average 43 cm (17 in), with substantial variation in average size from one region to another, and this pattern does not seem to follow any particular climatic rule and may be due to other environmental factors, such as predation and human encroachment. [16]

The platypus has an average body temperature of about 32 °C (90 °F) rather than the 37 °C (99 °F) typical of placental mammals . Research suggests this has been a gradual adaptation to harsh environmental conditions on the part of the small number of surviving monotreme species rather than a historical characteristic of monotremes.

Modern platypus young have three teeth in each of the maxillae (one premolar and two molars ) and dentaries (three molars), which they lose before or just after leaving the breeding burrow adults have heavily keratinised pads in their place. The first upper and third lower cheek teeth of platypus nestlings are small, each having one principal cusp, while the other teeth have two main cusps.The platypus jaw is constructed differently from that of other mammals, and the jaw-opening muscle is different. As in all true mammals, the tiny bones that conduct sound in the middle ear are fully incorporated into the skull, rather than lying in the jaw as in cynodonts and other premammalian synapsids . However, the external opening of the ear still lies at the base of the jaw.

The platypus has extra bones in the shoulder girdle, including an interclavicle , which is not found in other mammals.It has a reptilian gait, with the legs on the sides of the body, rather than underneath. When on land, it engages in knuckle-walking on its front feet, to protect the webbing between the toes.

Weight varies considerably from 0.7 to 2.4 kg (1.5 to 5.3 lb), with males being larger than females males average 50 cm (20 in) in total length, while females average 43 cm (17 in), [11] with substantial variation in average size from one region to another, and this pattern does not seem to follow any particular climatic rule and may be due to other environmental factors, such as predation and human encroachment. [16]

The platypus has an average body temperature of about 32 °C (90 °F) rather than the 37 °C (99 °F) typical of placental mammals. Research suggests this has been a gradual adaptation to harsh environmental conditions on the part of the small number of surviving monotreme species rather than a historical characteristic of monotremes.

Modern platypus young have three teeth in each of the maxillae (one premolar and two molars) and dentaries (three molars), which they lose before or just after leaving the breeding burrowadults have heavily keratinisedpads in their place. The first upper and third lower cheek teeth of platypus nestlings are small, each having one principal cusp, while the other teeth have two main cusps. The platypus jaw is constructed differently from that of other mammals, and the jaw-opening muscle is different. [11] As in all true mammals, the tiny bones that conduct sound in the middle ear are fully incorporated into the skull, rather than lying in the jaw as in cynodontsand other premammalian synapsids. However, the external opening of the ear still lies at the base of the jaw. The platypus has extra bones in the shoulder girdle, including an interclavicle, which is not found in other mammals. It has a reptilian gait, with the legs on the sides of the body, rather than underneath. When on land, it engages in knuckle-walking on its front feet, to protect the webbing between the toes.

While both male and female platypuses are born with ankle spurs, only the male’s spurs produce venom, omposed largely of defensin-like proteins (DLPs), three of which are unique to the platypus. The DLPs are produced by the immune system of the platypus. The function of defensins is to blow holes in pathogenic bacteria and viruses, but in platypuses they also are formed into venom for defense. Although powerful enough to kill smaller animals such as dogs, the venom is not lethal to humans, but the pain is so excruciating that the victim may be incapacitated. Oedema rapidly develops around the wound and gradually spreads throughout the affected limb. Information obtained from case histories and anecdotal evidence indicates the pain develops into a long-lasting hyperalgesia (a heightened sensitivity to pain) that persists for days or even months. Venom is produced in the crural glands of the male, which are kidney-shaped alveolar glands connected by a thin-walled duct to a calcaneus spur on each hind limb. The female platypus, in common with echidnas, has rudimentary spur buds that do not develop (dropping off before the end of their first year) and lack functional crural glands.

The venom appears to have a different function from those produced by nonmammalian species its effects are not life-threatening to humans, but nevertheless powerful enough to seriously impair the victim. Since only males produce venom and production rises during the breeding season, it may be used as an offensive weapon to assert dominance during this period.

Electrolocation

Platypus shown to children.

Monotremes (for the other species, see Echidna) are the only mammals (apart from at least one species of dolphin) [29] known to have a sense of electroreception: they locate their prey in part by detecting electric fields generated by muscular contractions. The platypus’ electroreception is the most sensitive of any monotreme.

The electroreceptors are located in rostrocaudal rows in the skin of the bill, while mechanoreceptors (which detect touch) are uniformly distributed across the bill. The electrosensory area of the cerebral cortex is contained within the tactile somatosensory area, and some cortical cells receive input from both electroreceptors and mechanoreceptors, suggesting a close association between the tactile and electric senses. Both electroreceptors and mechanoreceptors in the bill dominate the somatotopic map of the platypus brain, in the same way human hands dominate the Penfield homunculus map.

The platypus can determine the direction of an electric source, perhaps by comparing differences in signal strength across the sheet of electroreceptors. This would explain the characteristic side-to-side motion of the animal’s head while hunting. The cortical convergence of electrosensory and tactile inputs suggests a mechanism that determines the distance of prey that, when they move, emit both electrical signals and mechanical pressure pulses. The platypus uses the difference between arrival times of the two signals to sense distance. [31]

The platypus feeds by neither sight nor smell, [34] closing its eyes, ears, and nose each time it dives. [35] Rather, when it digs in the bottom of streams with its bill, its electroreceptors detect tiny electrical currents generated by muscular contractions of its prey, so enabling it to distinguish between animate and inanimate objects, which continuously stimulate its mechanoreceptors. [31] Experiments have shown the platypus will even react to an “artificial shrimp” if a small electrical current is passed through it. [36]

Recent studies say that the eyes of the platypus could possibly be more similar to those of Pacific hagfish or Northern Hemisphere lampreys than to those of most tetrapods. Also it contains double cones, which most mammals do not have. [37]

Although the platypus’ eyes are small and not used under water, several features indicate that vision played an important role in its ancestors. The corneal surface and the adjacent surface of the lens is flat while the posterior surface of the lens is steeply curved, similar to the eyes of other aquatic mammals such as otters and sea-lions. A temporal (ear side) concentration of retinal ganglion cells, important for binocular vision, indicates a role in predation, while the accompanying visual acuity is insufficient for such activities. Furthermore, this limited acuity is matched by a low cortical magnification, a small lateral geniculate nucleus and a large optic tectum, suggesting that the visual midbrain plays a more important role than the visual cortex like in some rodents. These features suggest that the platypus has adapted to an aquatic and nocturnal lifestyle, developing its electrosensory system at the cost of its visual system an evolutionary process paralleled by the small number of electroreceptors in the short-beaked echidna, who dwells in dry environments, whilst the long-beaked echidna, who lives in moist environments, is intermediate between the other two monotremes.


Top of the Monotremes

The platypus may not be the only monotreme with electroreception, but its sensory structures are the most complex.

About 40,000 specialized electroreceptor skin cells are arranged in stripes on the top and underside of its bill. Echidna species have anywhere from 2,000 to as few as 400, as is the case with the short-billed echidna. This species, which is found in dry habitats, has what researchers think is “no more than a remnant of this sensory system.”

Learn more about the senses of different species in our new exhibition Our Senses: An Immersive Experience.


Randomly Assembled and Surprisingly Dangerous: The Platypus

Besides looking like it was assembled from spare parts? We’ve all seen pictures of platypuses (yes, “platypuses”, not “platypi”) before, and everyone knows what total oddities they are: the duck-like bill, the beaver-esque tail, the fact that they lay eggs, despite being mammals but behind these weird traits lie… even more weird traits! So let’s take a moment to appreciate the lesser-known eccentricities of the platypus, shall we?

First off, these cuddly looking freaks are actually dangerous. Male platypuses have a spur on each hind foot which is filled with a venom powerful enough to kill a large dog. While it isn’t enough to take out a human, it does cause severe, incapacitating pain whose after-effects can last for months. One of only a very few venomous mammals, the male’s venom production increases during the breeding season, suggesting its purpose may lie in competition with other males.

Why your dog and your platypus shouldn’t play together.
(By Jason Edwards, via: How Stuff Works )

And speaking of breeding, reproduction in platypuses isn’t exactly ‘mammal standard’, either. Unlike all other mammals, which have two sex chromosomes (X and Y XX for females, XY for males, with rare exceptions), the platypus has ten. Talk about evolutionary overkill. A male platypus has the pattern XYXYXYXYXY, while a female has ten Xs. Researchers have found that the actual genetic structure of these sex chromosomes is actually more similar to birds than mammals, although 80% of platypus genes are common to other mammals.

After this alphabet soup of chromosomes arranges itself, up to three fertilised eggs mature in utero for about four weeks much longer than in most other egg-laying species (in birds, this may be only a day or two). Once laid, the eggs are only about the size of a thumbnail, and hatch in around ten days. While platypuses produce milk, they don’t actually have proper teats to suckle their babies- the fluid is released from pores in the skin. A small channel on the mother’s abdomen collects the milk, which is then lapped up by the young. Strangely, the babies are actually born with teeth, but lose them before adulthood. Such is the impracticality of platypus design…

Finally, let’s explore platypus hunting methods. Platypuses are the only mammals with the sixth sense of electroreception. Those leathery duck bills of theirs are actually precision receptors that can detect the electric fields created in the water by the contractions of muscles in their prey. Considering the prey in question is largely worms and insect larvae, we’re talking big-time sensitivity here. The bill is also very receptive to changes in pressure, so a movement in still water can be picked up in this way as well. Researchers have suggested that by interpreting the difference in arrival time of the pressure and electrical signals, the hunter may even be able to determine the distance of the prey. This would be especially useful, given that platypuses close both their eyes and ears when hunting. In fact, they won’t even eat underwater captured food is stored in cheek pouches and brought to land to be consumed.

So there you have it. The platypus: even weirder than you thought.

[Fun Fact:The female platypus has two ovaries, but only the left one works.]

Intelligent Design’s Worst Nightmare
(Via: Animal Planet )


Weird Animal Brain: Platypus

The platypus and the echidna are the only mammals that have the power of electroreception, which means they can sense electrical changes. Check out this new Weird Animal Brain to learn how the platypus uses its bill to catch prey underwater!

Scheich H., Langner G., Tidemann C., Coles R.B., Guppy A. (1986). Electroreception and electrolocation in platypus. Nature. 319(6052):401-2.

Pettigrew, J.D., Manger, P.R., and Fine, S.L. (1998). The sensory world of the platypus. Philosophical Transactions of the Royal Society B. 353(1372): 1199&ndash1210.


Tag: Platypus

Common Name : The Duck-Billed Platypus

A.K.A. : Ornithorhynchus anatinus

  • Only species of Family Ornithorhynchidae
  • Males average 50cm (20”) long, females 43cm (17”)
  • Weigh between 0.7 and 2.4kg (1.5 – 5.3lbs.)
  • Body temperature of 32 degrees Celcius five degrees lower than placental mammals
  • Live up to 17 years in captivity
  • Eat freshwater crustaceans, worms, and insect larvae

Found : Eastern Australia and Tasmania

It Does What?!

Besides looking like it was assembled from spare parts? We’ve all seen pictures of platypuses (yes, “platypuses”, not “platypi”) before, and everyone knows what total oddities they are: the duck-like bill, the beaver-esque tail, the fact that they lay eggs, despite being mammals but behind these weird traits lie… even more weird traits! So let’s take a moment to appreciate the lesser-known eccentricities of the platypus, shall we?

First off, these cuddly looking freaks are actually dangerous. Male platypuses have a spur on each hind foot which is filled with a venom powerful enough to kill a large dog. While it isn’t enough to take out a human, it does cause severe, incapacitating pain whose after-effects can last for months. One of only a very few venomous mammals, the male’s venom production increases during the breeding season, suggesting its purpose may lie in competition with other males.

Why your dog and your platypus shouldn’t play together.
(By Jason Edwards, via: How Stuff Works )

And speaking of breeding, reproduction in platypuses isn’t exactly ‘mammal standard’, either. Unlike all other mammals, which have two sex chromosomes (X and Y XX for females, XY for males, with rare exceptions), the platypus has ten. Talk about evolutionary overkill. A male platypus has the pattern XYXYXYXYXY, while a female has ten Xs. Researchers have found that the actual genetic structure of these sex chromosomes is actually more similar to birds than mammals, although 80% of platypus genes are common to other mammals.

After this alphabet soup of chromosomes arranges itself, up to three fertilised eggs mature in utero for about four weeks much longer than in most other egg-laying species (in birds, this may be only a day or two). Once laid, the eggs are only about the size of a thumbnail, and hatch in around ten days. While platypuses produce milk, they don’t actually have proper teats to suckle their babies- the fluid is released from pores in the skin. A small channel on the mother’s abdomen collects the milk, which is then lapped up by the young. Strangely, the babies are actually born with teeth, but lose them before adulthood. Such is the impracticality of platypus design…

Finally, let’s explore platypus hunting methods. Platypuses are the only mammals with the sixth sense of electroreception. Those leathery duck bills of theirs are actually precision receptors that can detect the electric fields created in the water by the contractions of muscles in their prey. Considering the prey in question is largely worms and insect larvae, we’re talking big-time sensitivity here. The bill is also very receptive to changes in pressure, so a movement in still water can be picked up in this way as well. Researchers have suggested that by interpreting the difference in arrival time of the pressure and electrical signals, the hunter may even be able to determine the distance of the prey. This would be especially useful, given that platypuses close both their eyes and ears when hunting. In fact, they won’t even eat underwater captured food is stored in cheek pouches and brought to land to be consumed.

So there you have it. The platypus: even weirder than you thought.

[Fun Fact:The female platypus has two ovaries, but only the left one works.]

Intelligent Design’s Worst Nightmare
(Via: Animal Planet )

Says Who?

  • Brown (2008) Nature 453: 138-139
  • Grant & Fanning (2007) Platypus . CSIRO Publishing.
  • Graves (2008) Annual Review of Genetics 42: 565-586
  • Moyal (2002) Platypus: The Extraordinary Story of How a Curious Creature Baffled the World . Smithsonian Press.

Haemoglobin degradation in monotremes

The semi-aquatic lifestyle of the platypus is supported by particularly high haemoglobin levels and large numbers of small red blood cells 31 . The haemoglobin–haem detoxification system in mammals provides efficient clearance to minimize oxidative damage 32 in which haptoglobin is the haemoglobin chaperone 32 and free haem is bound by haemopexin and alpha-1 microglobulin 33 .

Both the haemopexin and alpha-1 microglobulin genes are found in the monotreme genomes, whereas the haptoglobin gene is absent (Fig. 4b, Extended Data Fig. 10a, b and Supplementary Table 48), which suggests that monotremes evolved a haemoglobin clearance system that is different from that of other mammals. Haptoglobin evolved in the common ancestor of vertebrates from an immune gene of the MASP family 33 but has neofunctionalized in mammals to bind to haemoglobin with a higher affinity and to bind to the CD163A receptor, which is also absent in monotremes, for clearance in macrophages 34 . The absence of the haptoglobin gene and CD163A in monotremes suggests that the neofunctionalization of haptoglobin happened after the divergence of monotremes from therians, not before it as previously thought 34 , and long after the evolution of enucleated red blood cells in the common ancestor of mammals 35 . Several nonmammalian vertebrates have lost haptoglobin, including chicken 34 (Fig. 4b), in which an alternative, secreted CD163 family member, PIT54, is the haemoglobin-binding chaperone 33 . Phylogenetic analysis shows that monotremes lack genes that cluster with haptoglobin in the MASP family or a PIT54 orthologue (Extended Data Fig. 10c–e and Supplementary Table 50). We confirmed the expansion of the CD163 family in platypus 2 (ten members) and found five in echidna, compared with two and three in humans and mice, respectively (Extended Data Fig. 10e, f). As mammalian CD163A can bind to haemoglobin in the absence of haptoglobin 36 and one CD163 family member has become the haemoglobin chaperone in chicken, the CD163 family protein(s) may have evolved this role in monotremes.


Electroreceptors in the platypus

It has been known since the last century that the bill of the platypus contains densely packed arrays of specialized receptor organs and their afferent nerves. Until recently these were thought to be largely mechanoreceptive in function. However Scheich et al. 1 provide both behavioural and electrophysiological evidence that there are electroreceptors in the bill of the platypus. These authors were able to record evoked potentials from the somatosensory cortex of the brain in response to weak voltage pulses applied across the bill. Behavioural observations showed that a platypus could detect weak electric dipoles and it was suggested the animal was able to locate moving prey by the electrical activity associated with muscle contractions. From these observations, and in view of the fact that it was known that the bill contained gland receptors 2 which in several respects resembled the ampullary electroreceptors in freshwater fish, Scheich et al. concluded that the receptor array of the platypus bill included electroreceptors. In this report we present direct electrophysiological evidence for the existence of such receptors.


Electroreception

a sensory modality known to exist for certain aquatic vertebrates which provides an ability to detect weak electric fields in water. The origin of sensitivity may be traced to electroreceptors located in the skin of the organism.

Electroreception is limited to aquatic environments because on here is the resistivity of the medium is low enough for electric currents to be generated as the result of electric fields of biological origin. In air, the resistivity of the environment is so high that electric fields from biological sources do not generate a significant electric current. Electroreceptor are found in a number of species of fish, and in at least one species of mammal, the Duck-Billed Platypus. It is generally believed to be an ancient sensory modality that is related to, and perhaps derived from, the lateral line sense. Mammalian electroreceptors are independently derived. Thresholds can be as low as 0.01 microvolts per cm for some species of fish. Electroreceptors are rather insensitve to mechanical, light, chemical, and temperature. There are specific behaviors associated with electroreception, which include prey detection and predator avoidance. For those fishes with specialized electric organs, electroreception is also used for active object location and social communication.

Most animals do not have electroreceptors, but they may respond to strong electric shocks which activate bare nerve endings, pain receptors and other sense organs, non selectively.

Types of Electroreceptors
Type Where Found Sensitivity Structure
Ampullary Sharks & Rays
Non-teleost fishes (except holosteans)
Certain teleosts (mormyrids, certain notopterus, gymnotiforms, catfish)
Amphibians (except frogs and toads).
0.01 microvolt per cm in marine species, 0.01 millivolt/cm in freshwater sensitive to DC fields or to frequencies less than 50 Hz
Tuberous Mormyrid fish (Knollenorgans, Mormyromasts)
Gymnotiform fish (burst-duration coders, phase coders)
0.1 mV to 10 mV/cm.

Figures modified from Szabo (1965). R.C. = receptor cell b.m. = basement membrane n = nerve. The ampullary receptor has a jelly-filled canal leading to the skin surface the tuberous recepor has a loose plug of epithelial cells over the receptor organ.

References on Electroreceptors

Historical

Bullock, T. H., Hagiwara, S., Kusano, K. and Negishi, K. (1961). Evidence for a category of electroreceptors in the lateral line of gymnotid fishes. Science 134, 1426-1427.

Fessard, A. and Szabo, T. (1961). Mise évidence d'un récepteur sensible à l'électricité dans la peau d'un mormyre. C. rendu hebd. Séanc. Acad. Sci. Paris 253, 1859-1860.

Lissmann, H. W. and Machin, K. E. (1958). The mechanisms of object location in Gymnarchus niloticus and similar fish. Journal of Experimental Biology 35, 457-486.

Szabo, T. (1965). Sense organs of the lateral line system in some electric fish of the Gymnotidae, Gymnarchidae, and Mormyridae. J. Morphology. 117, 229-250.

Reviews

Bullock, T. H. and Heiligenberg, W. (1986). Electroreception. In Wiley Series in Neurobiology (ed. R. G. Northcutt). New York: John Wiley & Sons Inc.

Hopkins, C. D. (1983). Functions and mechanisms in electroreception. In Fish Neurobiology, vol. 1 (ed. R. G. Northcutt and R. E. Davis), pp. 215-259. Ann Arbor: Univ. of Michigan Press.

Hopkins, C. D. (1983). Sensory mechanisms in animal communication. In Animal Behaviour 2: Animal Communication, vol. 2 (ed. T. R. Halliday and P. J. B. Slater), pp. 114-155. Oxford: Blackwell Scientific Publications.


Watch the video: Great Mom Platypuses Laying Eggs And Cute Platypuses Moments (December 2021).