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Echolocation and Bioacoustics in Orcinus orca


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Orcas have been my passion from a very young age. I created this slideshow in eleventh grade and have since graduated with a BSc in marine biology. I am currently pursuing a career as a marine wildlife veterinarian and hope to specialize in orca health and conservation. Please contact me for use.

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Echolocation and Bioacoustics in Orcinus orca

  1. 1. Echolocation & Bioacoustics Orcinus orca Rebecca Crawford
  2. 2. Introduction • What Is Echolocation? • Killer Whale Classification • Orca Anatomy • Killer Whales Up Close • Whale called “Killer”
  3. 3. What is Echolocation?  the sophisticated, biological, sonar-like system used by dolphins, bats and other animals to detect and locate objects by emitting highpitched sounds that reflect off the object and return to the animal's sensory receptors  used in navigation, hunting and communication  killer whales and other dolphins can determine the location, direction, speed, size, shape and internal structure of another object or animal
  4. 4. Killer Whale Classification KINGDOM: Animalia animals PHYLUM: Chordata vertebrates CLASS: Mammalia mammals ORDER: Cetacea whales and dolphins SUBORDER: Odontoceti toothed whales FAMILY: Delphinidae oceanic dolphins GENUS: Orcinus scientific name: SPECIES: orca Orcinus orca
  5. 5. Orca Anatomy
  6. 6. Killer Whales Up Close  Largest member of the dolphin family  Average Male: 8-10 tonnes, 7-10 metres, 50-60+ years  Average Female: 4-6 tonnes, 6-8 metres, 80-90+ years Average 1.8 metres      Average 0.9 metres Extremely intelligent, social animals General activities: foraging, socializing, travelling, resting Found in all of the the world’s oceans Top of the food chain The most polluted animal on Earth (PBTs such as PCBs and DDT bioaccumulate in an orca’s body)  Status: some populations ENDANGERED, some THREATENED
  7. 7. Range Most widely distributed animal among marine mammals!
  8. 8. Whale called “Killer”  Efficient, deadly predators  40-52 teeth: 3-5 inches long, 1 inch diameter  Diet includes fish, birds, Cephalopods (octopi and squid), turtles, seals, sea lions, sharks, whales, porpoises, dolphins, deer, moose  A deliberate, fatal attack on a human by an orca in the wild has never been documented  Sleek, streamlined body ensures sheer speed (sometimes 45+ km/h)  Known as the “Wolves of the Sea” because they hunt in packs called PODS  Members of a pod stay together for life  Individuals per pod ranges from 2-100+  Two or more maternal groups may travel in SUBPODS  Two or more pods with similar dialects may travel in CLANS  Numerous pods have been spotted travelling in COMMUNITIES (500+)
  9. 9. Dorsal and Saddle
  10. 10. Frequency Detection Animal Frequency (Hertz) low high Humans 20 20 000 Whales/Dolphins 70 150 000 Seals/Sea Lions 200 55 000 Salmon/Fish <1 380
  11. 11. POD CATEGORIES Category I: Residents Category II: Transients Category III: Offshore
  12. 12. Distinct Pod Categories Resident Transient Offshore General Vicinity near shore, coastal waters off shore, coastal waters open ocean Average Count 5-50+ 2-7 30-60 Basic Diet primarily fish primarily marine mammals turtles, sharks, follow migratory patterns of salmon Vocal Expression frequent, loud very silent, single/cryptic clicks instead of many clicks frequent, loud Leader eldest female dominant male N/A Genetics unique from Transient unique from Resident some correspondence to Southern Residents Dorsal Fin curved and tapering tip straight tip rounded tip and multiple nicks Saddle Patch five patterns two patterns N/A
  13. 13. Resident Dorsal
  14. 14. Transient Dorsal
  15. 15. Offshore Dorsal
  16. 16. PACIFIC COAST - COMMONLY SIGHTED RESIDENTS & TRANSIENTS Resident Transient Pods A, A5, D, D1, AT1, O20 AB, AD05, AD16, AE, AI, AJ, AK, AN10, AN20, I31, G1, J, K, L Clans Northern: A, G, R N/A Southern: J Subpods A1, A4, A5, AB25 (occasionally travels with AJpod) N/A
  17. 17. Basic Sound Terminology
  18. 18. Sound  SOUND is a compressed wave in a medium (air, water).  Sound waves are longitudinal waves. In other words, the particles in the medium vibrate parallel to the direction of the motion of the wave.
  19. 19. Wave  A WAVE is a disturbance that transfers energy through a medium.  Waves are repeated over and over again.
  20. 20. Wavelength/Cycle • A WAVELENGTH or CYCLE is the shortest distance between any two points in the medium that are in phase. • A wavelength is measured from crest to crest or trough to trough. Pressure wavelength crest trough Time
  21. 21. Frequency     FREQUENCY is the number of complete wavelengths that pass a point in a given amount of time. Units: Hertz (Hz) or Kilohertz (kHz). Pitch is perceived frequency. The higher the frequency of the tone, the higher the audible pitch. Tone I: low pitch Tone II: high pitch
  22. 22. Converting Hertz to Kilohertz and Vice Versa Kilohertz = kHz Hertz = Hz 1 Kilohertz = 1 000 Hertz Therefore: 3.7 3 700 Hertz is _________ Kilohertz. 22 000 22 Kilohertz is _________ Hertz.
  23. 23. Amplitude  The AMPLITUDE is the distance from the rest position to the maximum point of the crest or minimum point of the trough.  The magnitude of a sound is associated with the size of its amplitude. Loud = high amplitude Quiet = low amplitude
  24. 24. Decibels  BELS and DECIBELS are a unit of sound intensity.  0.1 bel = 1.0 decibel  The smallest increase in sound intensity level that humans can distinguish is 1.0 decibel. Therefore, we measure sound intensity in decibels.
  25. 25. Spectrogram  A SPECTROGRAM is a visual record of a vocalization illustrating its power, frequency, and timing per phrase.
  26. 26. Oscillogram  An OSCILLOGRAM is a visual illustration of the variations in a vocalization produced using an oscilloscope.
  27. 27.  Clicks  Pulsed Calls  Tonal Sounds Whistles (close-range motivational sounds)
  28. 28. The Blowhole  The BLOWHOLE is the nostril located on the top of the rostrum. The blowhole is closed by the nasal plug when the orca dives underwater. When the orca surfaces, the the nasal plug retracts, enabling the whale to take a breath of air.
  29. 29. Sound Path Blowhole. Nasal sacs. Oil-filled melon. {OUTGOING} SOUND PATH. {INCOMING} SOUND PATH. Fat-filled cavity in lower jawbone. Auditory bulla/middle ear bones.
  30. 30. The Orca & Echolocation Killer whales do not possess vocal chords in the larynx. Clicking sounds are produced by the movement of air between the nasal passages and the blowhole. Some whistles and calls are produced by the movement of air in the larynx. Located below the orca’s blowhole are nasal sacs which produce clicks that are focused by the thick oil in the melon. The melon is then shaped to form an acoustic lens, which enables the orca to direct clicks towards a particular object. Echoes then reflect off of the object and are received through the lower jaw which focuses the image and sends it to the middle ear bones. This process allows the orca to form an acoustic image in its brain of its surroundings.
  31. 31. . . . outgoing sounds . . .
  32. 32. . . . incoming sounds . . .
  33. 33. Purpose Is there a correlation between the acoustics and behaviours of Orcinus orca?
  34. 34. Questions  How is it possible to distinguish between orca pods by analyzing         their acoustics? Is there a difference between the hunting vocalizations of Resident and Transient orcas? Do orcas possess a distinct vocabulary? Do orca clans possess a distinct dialect? How do acoustics play a role in maintaining the structure of a pod? Is it possible to identify an individual orca by its acoustics? Do male orcas produce different sounds than female orcas? Are distinct sounds produced between a mother orca and her calf? Do orcas produce a specific sound when pursuing their prey?
  36. 36. Variables  Independent *Hunting Vocalization Style (Resident versus Transient)  Dependent *Frequency (kHz) *Power (dB) *Average Time per Whistle (s) *Average Time Between Whistles (s) *Clicks (present or absent)
  37. 37. Hypothesis I predict that Resident and Transient orcas have unique hunting vocalization styles.
  38. 38. Procedure  Obtain digital-audio recordings of both Resident and      Transient orcas pursuing prey (source: internet). Use software (Raven Lite 1.0 – source: Cornell Laboratory of Ornithology, Cornell University, New York) to create spectrograms and oscillograms. Determine the frequency, power, and timing of the vocalizations from the spectrograms and oscillograms. Compare the observations to one another. Analyze and explain the differences and similarities. Draw conclusions and summarize.
  39. 39. The Hydrophone  The digital-audio sounds were recorded by scientists and researchers using a HYDROPHONE or “underwater microphone”.
  40. 40. Observations
  41. 41. Vocalizations Of Transient Orcas Communication Within A Pod Maximum Frequency: 6800 Hz Power Range: 85 dB – 115 dB Timing: 0.5 – 1.0 s whistles separated by 3-5 s of silence
  42. 42. Vocalizations Of Transient Orcas Foraging and Echolocating Maximum Frequency: 17000 Hz Power Range: 69 dB – 106 dB Timing: continuous, loud clicking and ten short whistles of 0.5 s, separated by 3 – 12 s of silence
  43. 43. Vocalizations Of Transient Orcas Foraging and Echolocating … a sea lion has been located! Maximum Frequency: 7000 Hz Power Range: 54 dB – 100 dB Timing: quiet, continuous clicking, two rising phrases: each 2 – 3 s in length, separated by 15 s of clicking
  44. 44. Vocalizations Of Transient Orcas Echolocating and Chasing Prey Maximum Frequency: 8500 Hz Power Range: 90 dB – 112 dB Timing: loud 1 – 2 s of tonal sounds separated by 3 – 5 s of quiet clicking
  45. 45. Vocalizations Of Transient Orcas Attacking and Killing Prey Maximum Frequency: 9000 Hz Power Range: 85 dB – 115 dB Timing: 2 s whistles separated by 3 – 4 s of silence
  46. 46. Transient Data Behaviour Presence / Absence of Clicking Sounds Maximum Frequency Minimum Power Maximum Power Average Length of Whistles Average Time Between Whistles (P / A) (kHz) (dB) (dB) (s) (s) 1 Communicating A 6.8 85 115 0.8 4.0 2 Foraging/ Echolocating P (Loud) 17 65 106 0.5 7.5 3 Foraging/ Echolocating… Prey Located P (Quiet) 7.0 54 100 2.5 15 4 Chasing Prey P (Quiet) 8.5 90 113 2.0 4.0 5 Attacking Prey A 9.0 85 115 2.0 3.5
  47. 47. Transients - A Summary  clicking sounds are present while orcas forage, when prey has been        located, and when orcas chase their prey clicking sounds are absent while orcas communicate and when orcas attack their prey Foraging/Echolocating: high frequency (17 kHz) Communicating/Prey Located/Attacking Prey: lower frequency (6.8 – 9.0 kHz) Power is lower when orcas are foraging and when prey has been located Power is higher when orcas are communicating or attacking prey When communicating and foraging, the time per whistle is shorter and the time interval between whistles is longer When chasing prey and attacking prey, the time per whistle is longer and the time interval between whistles is shorter
  48. 48. Vocalizations Of Resident Orcas Communication Within A Pod Maximum Frequency: 22000 Hz Power Range: 97 dB – 120 dB Timing: constant pulsed calls, whistles and clicks
  49. 49. Vocalizations Of Resident Orcas: A1, A4, A5 Subpods Foraging and Echolocating Maximum Frequency: 3700 Hz Power Range: 104 dB – 121 dB Timing: continuous whistles of 1.0 – 3.0 s, isolated and infrequent clicking
  50. 50. Vocalizations Of Resident Orcas: A Clan Foraging, Echolocating, and Feeding Maximum Frequency: 9500 Hz Power Range: 101 dB – 115 dB Timing: continuous 1.0 – 2.0 s whistles, isolated clicking
  51. 51. Vocalizations Of Resident Orcas: G Clan Foraging, Echolocating, and Feeding Maximum Frequency: 8500 Hz Power Range: 92 dB – 111 dB Timing: continuous whistles of 1.0 – 2.0 s
  52. 52. Vocalizations Of Resident Orcas: R Clan Foraging, Echolocating, and Feeding Maximum Frequency: 9000 Hz Power Range: 90 dB – 125 dB Timing: constant whistling of 1.0 – 3.0 s
  53. 53. Resident Data Behaviour Presence / Absence of Clicking Sounds Maximum Frequency Minimum Power Maximum Power Average Length of Whistles Average Time Between Whistles (P / A) (kHz) (dB) (dB) (s) (s) A 22 97 120 1.0 0.0 (Constant) 2 Foraging & Echolocating P (Isolated and Infrequent) 3.7 104 121 2.0 0.0 (Constant) 3 Foraging, Echolocating, and Feeding P (Isolated) 9.5 101 115 1.5 0.0 (Constant) 4 Foraging, Echolocating, and Feeding A 8.5 92 111 1.5 0.0 (Constant) 5 Foraging, Echolocating, and Feeding A 9.0 90 125 2.0 0.0 (Constant) 1 Communicating
  54. 54. Residents - A Summary  Clicking sounds are present while orcas forage/echolocate, and occasionally when they feed  Communicating: high frequency (22 kHz)  Foraging/Echolocating/Feeding: lower frequency (3.7 – 9.5 kHz)  Power varies while orcas forage, use echolocation, and feed  Power is highest when orcas communicate   When communicating, whistling is constant and the the length of the individual whistles is shorter When foraging, echolocating, and feeding, whistling is constant and the length of individual whistles is longest
  55. 55. Explanation
  56. 56. Recall… I hypothesize that Resident and Transient orcas have unique hunting vocalization styles.
  57. 57. Presence and Absence of Clicking RESIDENTS  Absent: communication, feeding  Present: echolocation, foraging (isolated and infrequent) TRANSIENTS  Absent: communication, attacking/killing prey  Present: echolocation, foraging (loud); chasing prey - (quiet) OBSERVATION: Both Resident and Transient orcas use echolocation to locate their prey, whether it be a school of fish or a humpback whale. Resident clicking seems to be infrequent whereas Transient clicking seems to be abundant.
  58. 58. Frequency RESIDENTS  3700 – 22000 Hz  highest when communicating TRANSIENTS  6800 – 17000 Hz  highest when foraging and echolocating EXPLANATION: Resident orcas use frequencies beyond the detection ability of their prey. Transient orcas however use frequencies at the low end of their prey’s frequency detection range.
  59. 59. Average Length Of Whistles RESIDENTS  1.0 – 2.0 s TRANSIENTS  0.5 – 2.5 s EXPLANATION: The average time per whistle is very similar for both Resident and Transient orcas. Resident and Transient killer whales are the same species. Transient orcas however, have adapted their behaviour and vocalizations due to their different taste in prey. Their vocalizations are suited to stalking their prey.
  60. 60. Comparing Average Time Between Whistles RESIDENTS  0.0 s (Constant)  Constant whistles and calls. TRANSIENTS  3.5 – 15 s of silence between individual whistles. EXPLANATION: Resident orcas feed primarily on fish, whereas Transient orcas feed primarily on marine mammals. Fish have poor underwater hearing compared to marine mammals. Thus, it makes sense that Transient orcas restrict their echolocation because their prey is extremely acoustically-sensitive.
  61. 61. Maximum Power RESIDENTS  Maximum Power: 111 – 125 dB TRANSIENTS  Maximum Power: 100 – 115 dB EXPLANATION: The maximum power is slightly higher for Resident orcas than Transient orcas. Fish, the primary prey of Resident orcas, have poor hearing. Therefore, the power of the Resident whales’ whistles, clicks, and calls do not affect their ability to locate their prey.
  62. 62. Minimum Power RESIDENTS  Minimum Power: 90 – 104 dB TRANSIENTS  Minimum Power: 54 – 90 dB EXPLANATION: The minimum power is distinctly lower for Transient orcas than Resident orcas. Marine mammals, the primary prey of Transient orcas, are extremely acoustically-sensitive. Therefore, the Transient whales restrict the power of their vocalizations to avoid being detected by their prey.
  63. 63. Frequency Detection Animal Frequency (Hertz) low high Humans 20 20 000 Whales/Dolphins 70 150 000 Seals/Sea Lions 200 55 000 Salmon/Fish <1 380 Transient Prey Resident Prey
  64. 64. Conclusion According to the observations, Resident orcas tend to be very vocal. Whistling and pulsed calls are fairly constant throughout their activities. Clicking is limited to low frequencies and used only for echolocation. Transient orcas are less vocal and tend only to produce short whistles and pulsed calls when attacking prey. Cryptic clicks (single, short) are abundant and produced at magnitudes at the low end of the frequency detection range of marine mammals. Therefore, Transients make an effort to conceal themselves. Due to the poor acoustic-sensitivity of the Residents’ prey, it is not necessary that they drastically modify their vocalizations. Therefore, Resident and Transient orcas have unique hunting vocalization styles.
  65. 65. Current Research RESIDENTS  flamboyant vocalization TRANSIENTS  restricted vocalization EXPLANATION: Compared to current projects performed by scientists and researchers, my analysis coincides. Resident killer whales tend to be more vocal than Transient killer whales due to the difference in the acoustic-sensitivity of their prey.
  66. 66. Thank You!
  67. 67. REFERENCES Adobe Reader. “Introduction.” Photographic and Acoustic Monitoring of Killer Whales in Prince William Sound and Kenai Fjords. 2001. 17 December 2006. <>. Adobe Reader. “Orca Natural History.” Current State of Our Orcas. 2000. 18 December 2006. <>. Cornell Lab of Ornithology. “Using Raven Lite.” Raven Lite 1.0 User’s Guide. 2006. 29 December 2006. <>. Dick, Gregg et al. Physics 11. Toronto: McGraw-Hill Ryerson, 2001. Russian Orcas Homepage. “Sound Production.” Killer Whale Acoustic Behaviour. 2007. 5 January 2007. <>. The Big Zoo. “Orcinus orca.” Killer Whale. 2007. 2 January 2007. <>.
  68. 68. REFERENCES Vancouver Aquarium. “AquaFacts: British Columbia’s Killer Whales (Orcinus orca).” Vancouver Aquarium. 2000. 18 December 2006. <>. Whale Watch Telegraph Cove: Stubbs Island Whale Watching. “Stellar Sea Lion Attack.” Transients. 2006. 27 December 2006. < start=1&tbnid=F4qdHX-tUmakXM:&tbnh=89&tbnw=123&prev=/images%3Fq%3Dtransient%2B%252 B%2Borcas%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DX>. Woods Hole Oceanographic Institution. “Seeing Sounds: Dolphins, Killer Whales and False Killer Whales.” Bioacoustics: Cetaceans and Seeing Sounds. 2004. 20 December 2006. <>. Workshop on Applications of Signal Processing to Audio and Acoustics. “Introduction”. Classification of Vocalizations of Killer Whales Using Dynamic Time Warping. 2005. 19 December 2006. < own/>.