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Philos Trans R Soc Lond B Biol Sci. 1998 July 29; 353(1372): 1199–1210.
PMCID: PMC1692312

The sensory world of the platypus.


Vision, audition and somatic sensation in the platypus are reviewed. Recent work on the eye and retinal ganglion cell layer of the platypus is presented that provides an estimate of visual acuity and suggests that platypus ancestors may have used vision, as well as the bill organ, for underwater predation. The combined electroreceptor and mechanoreceptor array in the bill is considered in detail, with special reference to the elaborate cortical structure, where inputs from these two sensory arrays are integrated in a manner that is astonishingly similar to the stripe-like ocular dominance array in primate visual of cortex, that integrates input from the two eyes. A new hypothesis, along with supporting data, is presented for this combined mechanoreceptive-electroreceptive complex in platypus cortex. Bill mechanoreceptors are shown to be capable of detecting mechanical waves travelling through the water from moving prey. These mechanical waves arrive after the electrical activity from the same prey, as a function of distance. Bimodal cortical neurones, sensitive to combined mechanical and electrical stimulation, with a delay, can thus signal directly the absolute distance of the prey. Combined with the directional information provided by signal processing of the thousands of receptors on the bill surface, the stripe-like cortical array enables the platypus to use two different sensory systems in its bill to achieve a complete, three-dimensional 'fix' on its underwater prey.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Catania KC. Structure and innervation of the sensory organs on the snout of the star-nosed mole. J Comp Neurol. 1995 Jan 23;351(4):536–548. [PubMed]
  • Gale JE, Ashmore JF. An intrinsic frequency limit to the cochlear amplifier. Nature. 1997 Sep 4;389(6646):63–66. [PubMed]
  • Gates GR, Saunders JC, Bock GR, Aitkin LM, Elliott MA. Peripheral auditory function in the platypus, Ornithorhynchus anatinus. J Acoust Soc Am. 1974 Jul;56(1):152–156. [PubMed]
  • Gregory JE, Iggo A, McIntyre AK, Proske U. Electroreceptors in the platypus. Nature. 326(6111):386–387. [PubMed]
  • Gregory JE, Iggo A, McIntyre AK, Proske U. Responses of electroreceptors in the platypus bill to steady and alternating potentials. J Physiol. 1989 Jan;408:391–404. [PubMed]
  • Krubitzer L, Manger P, Pettigrew J, Calford M. Organization of somatosensory cortex in monotremes: in search of the prototypical plan. J Comp Neurol. 1995 Jan 9;351(2):261–306. [PubMed]
  • Ladhams A, Pickles JO. Morphology of the monotreme organ of Corti and macula lagena. J Comp Neurol. 1996 Mar 4;366(2):335–347. [PubMed]
  • LeVay S, Voigt T. Ocular dominance and disparity coding in cat visual cortex. Vis Neurosci. 1988;1(4):395–414. [PubMed]
  • LeVay S, Wiesel TN, Hubel DH. The development of ocular dominance columns in normal and visually deprived monkeys. J Comp Neurol. 1980 May 1;191(1):1–51. [PubMed]
  • Manger PR, Hughes RL. Ultrastructure and distribution of epidermal sensory receptors in the beak of the echidna, Tachyglossus aculeatus. Brain Behav Evol. 1992;40(6):287–296. [PubMed]
  • Manger PR, Pettigrew JD. Ultrastructure, number, distribution and innervation of electroreceptors and mechanoreceptors in the bill skin of the platypus, Ornithorhynchus anatinus. Brain Behav Evol. 1996;48(1):27–54. [PubMed]
  • Manger PR, Collins R, Pettigrew JD. Histological observations on presumed electroreceptors and mechanoreceptors in the beak skin of the long-beaked echidna, Zaglossus bruijnii. Proc Biol Sci. 1997 Feb 22;264(1379):165–172. [PMC free article]
  • Little P. Genome analysis. Nature. 1996 Aug 1;382(6590):408–408. [PubMed]
  • Mogdans J, Bleckmann H, Menger N. Sensitivity of central units in the goldfish, Carassius auratus, to transient hydrodynamic stimuli. Brain Behav Evol. 1997;50(5):261–283. [PubMed]
  • MONTAGNA W, ELLIS RA. Sweat glands in the skin of Ornithorhynchus paradoxus. Anat Rec. 1960 Jul;137:271–277. [PubMed]
  • Pettigrew JD, Jamieson BG, Robson SK, Hall LS, McAnally KI, Cooper HM. Phylogenetic relations between microbats, megabats and primates (Mammalia: Chiroptera and Primates). Philos Trans R Soc Lond B Biol Sci. 1989 Nov 30;325(1229):489–559. [PubMed]
  • Scheich H, Langner G, Tidemann C, Coles RB, Guppy A. Electroreception and electrolocation in platypus. Nature. 319(6052):401–402. [PubMed]
  • Sivak JG. Accommodation in vertebrates: a contemporary survey. Curr Top Eye Res. 1980;3:281–330. [PubMed]
  • Vater M, Lenoir M. Ultrastructure of the horseshoe bat's organ of Corti. I. Scanning electron microscopy. J Comp Neurol. 1992 Apr 22;318(4):367–379. [PubMed]

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