Working donkeys are often associated with those living at or below subsistence levels. Small numbers of donkeys are kept for breeding or as pets in developed countries. A male donkey or ass is called a jack, a female a jenny or jennet; a young donkey is a foal.Jack donkeys are often used to mate with female horses to produce mules.he donkey has been used as a working animal for at least 5000 years. Of the more than 40 million donkeys in the world, about 96% are in underdeveloped countries, where they are used principally as pack animals or for draught work in transport or agriculture.
In simplistic language, every matter in this world vibrates, so that vibration we call frequency, and we measure it in Hz. The sound has its own frequency which is also measurable in Hz. The guy in the beginning of the video says that everything owes its existence to sound.
Normal human hearing ranges from 20 hertz to 20,000 hertz. Low-frequency sounds, below 20 hertz, are referred to as âinfrasoundâ and travel farther than high-frequency sounds. Frequencies above the range of human hearing (20,000 hertz) are referred to as âultrasonic.â.lthough the upper end of human hearing is about 20,000 hertz, deer can hear frequencies to at least 30,000 hertz. But, these high-frequency sounds must be louder because high-frequency sounds donât travel as far as low-frequency sounds. Hearing and Vocal Communication.