As reliable anaesthetic methods and delicate instruments to examine the nervous system have been developed, cats have been used to study a variety of neurological problems, such as epilepsy, deafness, and vision problems, making great contributions to our understanding of the nervous system.
David Hubel studied the development and function of the visual system in cats, finding that all mammals, including humans, are born with a partially-developed visual system. He built on information from previous detailed studies of the nervous systems of kittens, and found that proper development of the eyes, optic nerve and visual centres of the brain requires stimulation of the visual neurons by light. This work was awarded the Nobel Prize in medicine in 1981.
For many years vets treated cats with symptoms of feline leukeamia, where they were unable to isolate the virus. In 1986 researchers found that this disease was caused by a different retrovirus, which was similar to the HIV virus in humans. The retrovirus became known as feline AIDS (T-lymphotropic lenti virus), and is thought to be transmitted through bite wounds, although the virus can remain dormant for years before causing disease, so there may be other routes of infection. FIV is not transmissible to humans, but the virus is genetically similar to HIV, and diseases caused by the virus are very similar. Cats which are naturally infected with the FIV virus are used as models to study effective anti-viral treatments for AIDS, which will benefit both cats and humans. The recent development of an FIV vaccine has given a potential new model for use in HIV vaccine development.
Cats were used in research to better understand how the brain combines information from the two ears, including sound localisation. Cats are used because of their extraordinary talents at localising sounds. Feral cats likely do most of their hunting at night because that is when their rodent prey is most active. Because vision at night is limited, hearing is the primary sensory cue for the cat to localise its prey. The cat auditory system is very similar to that of humans, making it relevant to clinical studies of humans with bilateral cochlear implants.
The relatively long life span of cats, compared with mice and rats, makes it possible to observe the slower and more subtle effects of aging. Cats are known to reach the age of 16-20 years, and advances in treating many feline diseases have extended their life-expectancy.
Cats are mainly used as models to study sensory systems and neuroscience. They have acute hearing, excellent eye-sight and highly developed balance and spatial awareness. These highly developed senses have always interested scientists, and more is known about the anatomy of the cat's sensory systems than those of any other animal. Cats also have well developed cognitive abilities and memories, and have often been used in laboratory tests of learning ability, with results which have been applied to human educational practices.
Performing experiments in cats, other animals and eventually man, Alexis Carrel changed surgical procedures, and made it possible for lost limbs to be re-attached. Before Carrel's discoveries, circulation could not be established through transplanted tissue. He developed a new surgical technique which allowed blood vessels to be attached to a functioning circulation system.
He later turned his attention to transplant surgery, and found that although it was possible to remove and reattach organs or limbs from an animal, transplants between animals of the same species led to complications and rejection of the foreign tissue. Many of his experiments concerned kidney transplants, and the lifesaving operation which is commonplace today would never have been possible without his work.
The tongues of most mammals hold taste receptors— Humans enjoy five kinds of taste buds (possibly six): sour, bitter, salty, umami (or meatiness) and sweet (as well as possibly fat).Whether as a result of this dietary choice or the cause of it, all cats—lions, tigers and British longhairs — lack the DNA of one of the two proteins that make these taste receptors. As a result, it does not permit cats to taste sweets. "They don't taste sweet the way we do," says Joe Brand, biochemist and associate director at the Monell Chemical Senses Centre in Philadelphia. Cats may lack other components of the ability to enjoy (and digest) sugars, such as glucokinase in their livers—a key enzyme that controls the metabolism of carbohydrates and prevents glucose from flooding the animal.
However, cats can taste things we cannot, such as adenosine triphosphate (ATP), the compound that supplies the energy in every living cell. "There isn't a lot hanging around in meat, but it's a signal for meat," Brand says. And plenty of other animals have a different array of receptors, from chickens that also lack the sweet gene to catfish that can detect amino acids – linked to rotting food - in water at nanomolar concentrations.
Scientists said that having a cat helped to relieve stress and anxiety, which is known to help protect against heart disease by lowering blood pressure and reducing the heart rate. Owning a cat can reduce the risk of heart attacks and strokes by more than a third, researchers have found. One reason could be that stroking the pet could cut the level of stress-related hormones in the blood. Reducing stress is known to help protect against heart disease by lowering blood pressure and reducing the heart rate.
Cats have 3 eye lids, two outer ones, and one inner one. This last one, also known as the third eyelid or ‘haw’, plays an important role in maintaining the health of their eye surface. It is so important that among mammals and birds, the norm is having three eyelids and not two – we are the odd one out.