Comments on: Tuning in to squirrels http://www.p2pnet.net/story/2022 p2pnet.net offers not-your-lamescream news on movies music digital media P2P peer-to-peer TV television file sharing freedom of speech open source product news Wifi mobiles company Sun, 07 Sep 2008 08:08:30 +0000 http://wordpress.org/?v=2.2.1 By: Reader's Write http://www.p2pnet.net/story/2022#comment-5100 Reader's Write Sat, 04 Sep 2004 22:00:19 +0000 http://www.p2pnet.net/story/2022#comment-5100 In fact ultrasonic frequencies are present in human screams. we are unaware of that energy because we are more sensitive to lower frequencies. Human can indeed hear ultrasound, but generally only by bone or fluid conduction to the ear (lenhardt et al, 1991 Science) In fact ultrasonic frequencies are present in human screams. we are unaware of that energy because we are more sensitive to lower frequencies. Human can indeed hear ultrasound, but generally only by bone or fluid conduction to the ear (lenhardt et al, 1991 Science)

]]> By: Reader's Write http://www.p2pnet.net/story/2022#comment-3753 Reader's Write Fri, 30 Jul 2004 08:16:12 +0000 http://www.p2pnet.net/story/2022#comment-3753 I would probably disagree with the significance of the concept of "ultrasonic" as it relates to animals. Each species has its own individual range of hearing - an audible frequency range that often may be outside of the human range of hearing. The terms "ultrasonic" and "subsonic" apply to the range of human hearing only, so these terms might not be appropriate when referring to other species' interactions. From tiny insects to great whales, many animals communicate using ultrasonic frequencies. Elephants use subsonic frequencies for the purpose of locating each other that can be audible (to them) for miles. Maybe if the range of human hearing was not so genetically limited, we would not be using the label "ultrasonic" nearly as much. The ground squirrels mentioned converse at 50 khz, which is only just barely outside the measured audible range of domestic dogs, for instance - so perhaps some predators in the wild can actually hear the squirrrels, as evolutionary natural selection would probably favor this ability. Audible range for various animals in hertz: Humans 20- 20,000 Cats 100- 32,000 Dogs 40- 46,000 Horses 31- 40,000 Elephants 16- 12,000 Cattle 16- 40,000 Bats 1,000- 150,000 Grasshoppers and locusts 100- 50,000 Rodents 1,000- 100,000 Whales and dolphins 70- 150,000 Seals and sea lions 200- 55,000 I would probably disagree with the significance of the concept of “ultrasonic” as it relates to animals. Each species has its own individual range of hearing - an audible frequency range that often may be outside of the human range of hearing. The terms “ultrasonic” and “subsonic” apply to the range of human hearing only, so these terms might not be appropriate when referring to other species’ interactions.

From tiny insects to great whales, many animals communicate using ultrasonic frequencies. Elephants use subsonic frequencies for the purpose of locating each other that can be audible (to them) for miles. Maybe if the range of human hearing was not so genetically limited, we would not be using the label “ultrasonic” nearly as much.

The ground squirrels mentioned converse at 50 khz, which is only just barely outside the measured audible range of domestic dogs, for instance - so perhaps some predators in the wild can actually hear the squirrrels, as evolutionary natural selection would probably favor this ability.

Audible range for various animals in hertz:

Humans 20- 20,000
Cats 100- 32,000
Dogs 40- 46,000
Horses 31- 40,000
Elephants 16- 12,000
Cattle 16- 40,000
Bats 1,000- 150,000
Grasshoppers and locusts 100- 50,000
Rodents 1,000- 100,000
Whales and dolphins 70- 150,000
Seals and sea lions 200- 55,000

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