At least two institutions have researched the effects of a cat's purr: Fauna Communications Research Institute in the USA, and The University of Warwick here in the UK.

The team at the Fauna Communications Research Institute in North Carolina have discovered that cats purring is a 'natural healing mechanism.'

Wounded cats will purr because it helps to heal and strengthen bones and organs. Exposure to similar sound frequencies is known to improve bone density in humans, heal bone fractures and control pain. Purring is believed to have a similar effect to ultra-sound treatment on humans.

Only two years ago scientists discovered that vibrations between 20-140 Hz (at low db) are anabolic for bone growth and will also help to heal fractures, mend torn muscles and ligaments, reduce swelling, and relieve pain. Fauna have found that a cat's purr not only matches this vibration, but its dominant frequencies are 25 and 50 Hz - the optimum frequencies for bone growth and fracture healing. All cats, including larger ones such as pumas, ocelots and lions, have further sets of strong harmonics at the exact hertz (number of cycles per second) that generate muscle strength, increase joint mobility and provide therapeutic pain relief.

The healing implications for sick humans are exciting, and the fact that many of the new 'sound healing' therapies incorporate toning and overtoning is an interesting footnote. Scientists are now researching whether sound and vibration therapy could halt osteoporosis, or renew bone growth in post-menopausal women and the elderly. "We're bound to learn fantastic things if we are able to genuinely communicate with another intelligent species," says the Institute. "We also hope to provide the world with a whole new generation of non-invasive, simple and affordable healing methods."

Ultimately, through its work with language structure, the Research Institute hopes to create 'common languages' between humans and animals. This would offer a unique learning opportunity and, the team hopes, foster greater respect for the animal kingdom. "Humans tend to equate communication with intelligence - perhaps the public would do more to protect these creatures if they consider them knowing."

Fauna Communications is a non-profit research institute and can be contacted at Fauna Communications Institute, PO box 1126, Hillsborough, NC 27278, USA. www.animalvoice.com.

Dr June McNicholas of the University of Warwick found from research how non-human relationships can be as significant as those we have with other humans, particularly for older people. Her work over the past decade in the area of pets and residential care for the elderly has led to an increase in understanding by care workers of the crucial role that pets can play in older people's lives. It also led to an increase in the number of residential care homes that will accept pets. Research carried out by Dr McNicholas in Wales a few years ago found that 57% of residential homes have a policy about pets and, that two-thirds would accept pets, including cats.

Her research has discovered some important therapeutic benefits of cat companionship. She and her colleagues found that:

• Cats can provide considerable emotional support during the early stages of spousal bereavement.
• Cats can provide support for women with breast cancer.
• Cat owners have fewer psychological and physical health problems.
• 90% of children with cats rate their feline as being in their top ten special friends.

A study by the Institute of Paediatrics and Adolescent Medicine in Munich found that young children who were continuously exposed to cats were 67% less likely to develop allergic asthma and 45% of them were not as susceptible to developing hay fever as other children.