Vocalisation As A Welfare Indicator

Vocalisation = the active generation of sound with specific organs

Sounds = pressure wave traveling through a medium created by a vibrating object Basically pressure waves in sound are a series of molecules squeezed together (compression) and pulled apart (rarefaction) which causes molecules next to them to do the same thing sending the motions to the next molecules and so on

Sound will eventually hit the eardrum causing the inner workings of the ear to vibrate like the molecules

Sound is ideal for communication with conspecifics at a distance since it carries and is relatively insensitive to objects in its way Sound is good for animals to communicate since it travels far and through many different mediums

Amplitude is the size of the vibration

How much energy is in the sound

Amplitude determines the volume of the sound

Frequency is the speed of vibrations

Frequency is a measure of how many compressions and rarefactions are in a given period of time

Hertz or Hz

How many wavelengths (compression and rarefaction cycles) occur in 1 second

Frequency determines pitch The higher the frequency the more wavelengths occur The higher the frequency the higher the pitch

When objects vibrate they can cause either secondary vibrations or harmonics

Secondary vibrations and harmonics produced will be exact multiples of the first sound or the lowest frequency of sound An example is that the first harmonic (the original sound) could be 50Hz followed by a second harmonic at 100Hz which is followed by a third harmonic at 150Hz and so on The copies are multiplied in frequency compared to the copy/original they’re being duplicated from It’s like if the first/fundamental sound was the smallest russian doll and the second vibrations/harmonics are all the other dolls getting bigger in a set order/multiple of the previous dolls size

Lungs Trachea Larynx

To generate sound first you’d exhale air from the Lund and trachea The animal can control the air flow, to some extent, so it can control the speed and force at which it leaves the body The air will travel up the trachea and into the larynx As the air passes through the larynx it will vibrate vocal folds in the larynx The vibrations generated by the vocal folds of the larynx will generate the fundamental frequencies and the harmonics

Generate and control the air flow The lungs and trachea are used for respiration

Phonation

The production or utterance of speech sounds

After passing through the larynx the air will pass through the vocal tract The vocal tract is all the structures between the larynx and the opening of the mouth

Within the vocal tract the sound will be filtered by dampening some parts of the sound and amplifying other parts of the sound

Resonance

Tongues Lips Teeth Jaw Hard and soft palate

Amplitude Volume Duration of the sound Fundamental frequency Respiration