

Preview text:
ə pən ʊ  jɔːr aɪz n ɪ siː ˈw tə ɔː r ænd t ɪ ɪz d ˈ f ɪ kəlt ɪ
 tuː siː mʌʧ mɔː ðæn ə ˈmɜːki, bl ˈ əri ɪ  r ɡ i n ː ˈk lə ʌ . sa ndz ʊ , tuː, ɑː  b ˈɡɑː ld ᵊ ænd d ˈ f ɪ kəlt ɪ  tuː ˌk mpr ɒ h ɪˈ nd ɛ . w ða ɪˈ t ʊ ˈsp la ɛʃᵊ ɪzd  kw ɪˈ pmənt ɪ  hju ˈ mənz ː  wʊd bi l ː st ɒ n ɪ ðiːz di p ː siː ˈhæb tæts ɪ , səʊ haʊ duː ɪʃ  f meɪk t ɪ  siːm səʊ i ˈ zi ː ? mʌʧ v ɒ ðɪs ɪz djuː tu ə  ː ba ˌ ə ɪ l ʊˈ kəl ɒʤɪ  f n ɪˈ m ɒ nən ɪ  nəʊn æz electror eception – ði ə b ˈ l ɪ ti ɪ tuː pə si ˈ v ː ænd ækt əˈpɒn l ɪˈ ɛktr kəl ɪ  st ˈ ɪmjʊlaɪ æz p t ɑː v ɒ ði ˈəʊ vər l ɔː ˈsɛns z
ɪ . ðɪs əˈbɪlɪti ɪz ə ˈ ʊnli faʊnd n ɪ ə kwæt ˈ ɪk ɔːr æm f ˈ ɪbɪəs spi ˈ i ːʃ z ː b k ɪˈ z ɒ ˈ wɔːtər ɪz ən f ɪˈ ɪʃənt kənˈd ktə ʌ r v ɒ l ɪ ɛkˈtr s ɪ ti ɪ .
Open your eyes in sea water and it is difficult to see much more than a murky, bleary 
green colour. Sounds, too, are garbled and difficult to comprehend. Without 
specialised equipment humans would be lost in these deep sea habitats, so how do 
fish make it seem so easy? Much of this is due to a biological phenomenon known as
electroreception – the ability to perceive and act upon electrical stimuli as part of the 
overall senses. This ability is only found in aquatic or amphibious species because 
water is an efficient conductor of electricity. Electroreception k mz ʌ  n ɪ tuː ˈveər ənts ɪ . wa l ɪ l ɔː æn ˈ ɪməlz ( n ɪ ˈklu d ː ɪŋ hju ˈ mənz ː ) ˈʤɛ nəre t ɪ l ɪˈ ktr ɛ k ɪ s ˈ nlz ɪɡ , bɪ k ˈ z ɒ ðeɪ ɑːr m ɪˈ t ɪ d ɪ baɪ ðə n ˈ ɜːvəs s ˈ ɪstəm, s m ʌ æn ˈ ɪməlz 
hæv ði əˈbɪlɪti – nəʊn æz pæs ˈ v
ɪ electroreception – tuː r si ɪˈ v ː ænd ˈdi kə ː d ʊ l ɪˈ ɛktr k ɪ ˈ sɪɡnlz  nəre ˈʤɛ t ɪ d ɪ baɪ ðə ˈʌ r æn ˈ ɪməlz n ɪ ˈɔːdə tuː s ns ɛ  ðeə lə ke ʊˈ n ɪʃᵊ .
Electroreception comes in two variants. While all animals (including humans) 
generate electric signals, because they are emitted by the nervous system, some 
animals have the ability – known as passive electroreception – to receive and decode
electric signals generated by other animals in order to sense their location. ðə ˈʌ  kri ˈ əz ːʧ  kæn ə ɡ ʊ f ˈ ðə ɜː  st l
ɪ , haʊˈɛvə. æn ˈ ɪməlz w ð ɪ ˈækt v ɪ electroreception  pəˈz s ɛ b ˈ d ɒ ɪli  ənz ˈɔːɡ  ðæt ˈʤɛnəre t ɪ ˈspɛʃəl l ɪˈ ɛktr k ɪ s ˈ nlz ɪɡ  n
ɒ kjuː. ðiːz kæn biː juː zd f  ɔː ˈmeɪtɪŋ s ˈ nl ɪɡ z ænd t ˌ ɛr t ɪˈ r ɔː əl ɪ dɪsˈpleɪz æz w l ɛ æz lə ke ʊˈ t ɪ ŋ ɪ ˈɒb kts ʤɪ  n ɪ ðə 
ˈwɔːtə. ˈæktɪv electroreceptors kæn d ˌ ɪfəˈr n ɛ ʃɪeɪt b twi ɪˈ n ː ðə ˈveərɪəs r z ɪˈ stəns ɪ z ɪ ðæ t ðeər l ɪˈ ɛktr kəl ɪ  k ˈ rənts ʌ  ɪnˈka ntə ʊ . ðɪs kæn h lp ɛ ð m ɛ a d ɪˈ nt ɛ fa ɪ ɪ w ˈ ð ɛ ər ə n ˈ ðə ʌ  kri ˈ ː ə ʧ r ɪz preɪ, pr ˈ dətə ɛ r ɔː s ˈ ʌmθ ŋ ɪ ðæt ɪz b st ɛ lɛft əˈlə n
ʊ . ˈæktɪv electroreception hæz  ə re n ɪ ʤ v ɒ əˈbaʊt w n ʌ ˈb di ɒ l ŋθ ɛ  – ju ˈ əli ːʒʊ   st ʤʌ n ɪˈ f ʌ tuː  v ɡɪ ɪts həʊst ta m ɪ tuː  t ɡɛ  a t ʊ v ɒ ðə weɪ ɔː ə ɡ ʊ n ɪ fɔː ðə k l ɪ .
Other creatures can go further still, however. Animals with active electroreception 
possess bodily organs that generate special electric signals on cue. These can be 
used for mating signals and territorial displays as well as locating objects in the 
water. Active electroreceptors can differentiate between the various resistances that 
their electrical currents encounter. This can help them identify whether another 
creature is prey, predator or something that is best left alone. Active electroreception 
has a range of about one body length – usually just enough to give its host time to 
get out of the way or go in for the kill. wʌn fæs ˈ ne ɪ t ɪ ŋ ɪ juːz v ɒ ækt ˈ
ɪv electroreception – nə n ʊ æz ðə  æm ˈʤ ŋ ɪ əˈv dəns ɔɪ  rɪ
sˈpɒns ˈmɛkənɪzm – hæz bi n ː əbˈzɜːvd b twi ɪˈ n ː m ˈ ɛmbəz v ɒ s m ʌ spi ˈ i ːʃ z ː nə n ʊ æz ð ə ˈwiːkli l
ɪˈ ɛktrɪk fɪʃ. wɛn tu s ː ʌʧ l ɪˈ ktr ɛ k ɪ fɪʃ mi t ː n ɪ ði ə ˈ ən ʊʃ  ju ˈ z ː ŋ ɪ ðə se m ɪ fri ˈ kwən ː si, iːʧ fɪʃ w l ɪ ð n ɛ ʃɪft ðə ˈfri kwənsi ː  v
ɒ ɪts dɪsˈʧɑːʤ səʊ ðæt ðeɪ ɑː trænz m ˈ t ɪ ŋ ɪ n ɒ ˈd
ɪfrənt ˈfriːkwənsiz. du ˈ ːɪŋ səʊ pr v ɪˈ nts ɛ
 ðeə electroreception fækəltiz ˈ  fr m ɒ bɪˈkʌmɪŋ  æmd ʤ . l ŋ ɒ b f
ɪˈ ɔː ˈsɪtɪznz bænd ˈreɪdɪəʊ ju ˈ zəz ː  f st ɜː hæd tuː j l ɛ  “ t ɡɛ f ɒ maɪ fri ˈ kwə ː nsi!” æt hæpl ˈ s ɪ ˈnɒvɪsɪz ˈkl tər ʌ ŋ ɪ ði eə we vz ɪ , æt liːst w n ʌ spi ˈ i ːʃ z ː hæd faʊnd ə weɪ  tuː ˈpiːsf li ʊ ænd ˈkwɪkli rɪˈz lv ɒ ðɪs ta p ɪ v ɒ d s ɪ pju ˈ t ː . 
One fascinating use of active electroreception – known as the Jamming Avoidance 
Response mechanism mɛkənɪzm – has been observed between members of some 
species known as the weakly electric fish. When two such electric fish meet in the 
ocean using the same frequency, each fish will then shift the frequency of its 
discharge so that they are transmitting on different frequencies. Doing so prevents 
their electroreception faculties from becoming jammed. Long before citizens’ band 
radio users first had to yell “Get off my frequency!” at hapless novices cluttering the 
air waves, at least one species had found a way to peacefully and quickly resolve this type of dispute.