How Does the Walrus How Does the Walrus Hear?Hear?

What Does the What Does the Walrus Say?Walrus Say?

Walrus HearingWalrus Hearing

Little knownLittle known Only one study and Only one study and

probably not entirely probably not entirely accurate. accurate.

AmphibiousAmphibious AerialAerial UnderwaterUnderwater

Outer and Middle EarOuter and Middle Ear

Sound vibrations travel to the pinna.Sound vibrations travel to the pinna. Sound is channeled to the ear drum Sound is channeled to the ear drum

(tympanic membrane)(tympanic membrane) Sound is amplified and travels across 3 Sound is amplified and travels across 3

bonesbones Malleus, Incus, StapesMalleus, Incus, Stapes

The Inner EarThe Inner Ear

CochleaCochlea Oval windowOval window

Doorway to CochleaDoorway to Cochlea Basilar MembraneBasilar Membrane

Vibrations lead to pitch and tone detectionVibrations lead to pitch and tone detection Hair CellsHair Cells

Bend as the basilar membrane rubs togetherBend as the basilar membrane rubs together Auditory NerveAuditory Nerve

Hair cells that bend release CaHair cells that bend release Ca++ that relays the that relays the message to the brain.message to the brain.

Cochlea-straightenedCochlea-straightened

Adaptations in WaterAdaptations in Water

Bone ConductanceBone Conductance Reduced PinnaReduced Pinna

Questions On HearingQuestions On Hearing

Do they Talk?Do they Talk?

NO!NO! Walruses communicateWalruses communicate

SoundsSounds TouchTouch SmellSmell BehaviorBehavior

ActivityActivity

Break into groupsBreak into groups Come up with sounds that you think a Come up with sounds that you think a

walrus would makewalrus would make Must give a demo of the soundMust give a demo of the sound Why does this sound matter?Why does this sound matter?

My ResearchMy Research

Study PinnipedsStudy Pinnipeds Pacific WalrusPacific Walrus Pacific Harbor SealPacific Harbor Seal California Sea LionCalifornia Sea Lion

Record Underwater SoundsRecord Underwater Sounds Look for Ultrasonic frequenciesLook for Ultrasonic frequencies Catalog the Repertoire at Higher Catalog the Repertoire at Higher

FrequenciesFrequencies

BackgroundBackground

Males are typically Males are typically vocal to attract vocal to attract females during females during breeding seasonbreeding season Pick up linePick up line

No studies on No studies on femalesfemales

Very vocal animalsVery vocal animals

GoalsGoals

To record underwater To record underwater sounds to look for sounds to look for ultrasonic ultrasonic components and components and potential use towards potential use towards echolocation.echolocation.

To observe behaviors To observe behaviors in attempt to in attempt to understand function understand function of sounds produced. of sounds produced.

MaterialsMaterials

Ithaco 605 Hydrophone- Ithaco 605 Hydrophone- Ultrasonic frequency Ultrasonic frequency response. response.

DELL XPS M140 Laptop.DELL XPS M140 Laptop. Goldwave sound analysis Goldwave sound analysis

program and recording program and recording software. software.

Spectrogram sound Spectrogram sound analysis program. analysis program.

MethodsMethods

Recordings taken Recordings taken during Spring and during Spring and Summer months of Summer months of 2006 at Brookfield 2006 at Brookfield Zoo between 6-10AM.Zoo between 6-10AM.

Behavioral notes Behavioral notes taken as needed as taken as needed as well as video. well as video.

What do I do with the What do I do with the datadata

Listen to sound filesListen to sound files Identify SoundsIdentify Sounds Analyze with Analyze with

SoftwareSoftware Identify certain Identify certain

featuresfeatures Run statistical testsRun statistical tests

Similar and differentSimilar and different

Glugs by JoanGlugs by Joan

Unclassified SoundUnclassified Sound

ConclusionsConclusions

Walruses make really Walruses make really cool soundscool sounds

Still not sure whyStill not sure why Much of it isn’t Much of it isn’t

ultrasonicultrasonic

Just for funJust for fun

QUESTIONS?QUESTIONS?

Mehgan Clark: MM-NOOK@WIU.EDU