By David Rep Ha'Artez
The cat - is the winter hot? Shoner Sheva
By David Ref
The feet of the Canadian Lynx, a species of cat that lives in North America, look like shoes bought at a camping equipment store. The schooner is able to spread his toes to the sides and increase the surface area of his feet. This is how his body weight (about 10 kg on average) is distributed over a large surface area and this helps him move on top of the snow without sinking into it.
The European schooner is twice as large as its Canadian relative. It seems that the reason for the relatively small dimensions of the Canadian species (up to about a meter in length and about half a meter in height) lies in its specialization in hunting the "snow hare" - whose name implies that it is also not bad at covering distances in the frozen north.
A study whose results were published in the last issue of the journal "PNAS" examined the effects of weather conditions on the populations of the Canadian schooner and its prey. It seems that changes in the difficulty of the snow and its compactness also affect the schooner's ability to hunt rabbits.
The research, supported by the University of Oslo, lasted between 1987 and 1996 and was carried out in northwestern Canada. For eight winters, the researchers examined the hunting success rate of the schooners tested and the climate changes in the area. They measured the prey capture success rate and other metrics: the temperature, the difficulty of the snow, its depth and the degree to which the schooner's feet sink into the snow when chasing a rabbit.
The researchers discovered that in a relatively cold winter the success rate of the schooners in catching rabbits was low compared to warm winters. The reason: in cold weather, most of the time a fresh layer of crisp snow remains, and in this situation the rabbits have a relative advantage over the schooner. They are good at running on snow and in many cases manage to escape, while the schooners have difficulty developing sufficient speed, because they sink in the snow. In relatively warm winters, when the snow did not pile up repeatedly, a relatively hard layer of ice formed on the surface of the ground, the running ability of the schooners in relation to the hares improved, and the game catch rate increased.
The Canadian schooner, which used to live all over the North American continent, is now mostly common in Western Canada. The schooner can walk about 8 km per day in search of prey, and individuals have been recorded that traveled a distance of about 500 km during a season. However, it seems that the population living in Western Canada does not tend to leave the area of the "territory", whose invisible border is south of Hudson Bay. It seems that their establishment in one area is related to their reliance on the rabbit population, which are their main prey.
The new research shows that the schooners benefit from the phenomenon of global warming: their hunting ability should improve with the changes in the weather. However, increased hunting of rabbits, on which the shoonari population depends, could lead to a food crisis. It will inevitably be followed by a decrease in the size of the schooner population.
50 thousand dollars and the domestic cat is cloned
By David Ref
At first, the results of the experiment seemed somewhat puzzling: the exact copy of Rainbow the cat - a cloned cat that was born healthy - certainly did not look the same as the "mother", the donor of the genes. Awkward, because apparently the two are supposed to look exactly the same. In fact, this was another proof of what researchers have known for a long time: the fur pattern in cats is not only influenced by the genetic load but also by environmental factors. However, several days passed, during which the young cat was tested, before word of the first successful clone of a domestic cat was published.
The cat's name is Cc, short for copycat (and also a reference to the "copy" line in an email). Copycat was born on December 22, 2001, the only one of more than 80 embryos to survive the cloning and gestation process, which was done by researchers at the University of Texas.
A cell nucleus taken from Rainbow the cat was transplanted into an egg cell of another cat, instead of the original cell nucleus. This process was carried out dozens of times, and the embryos were implanted in the uterus of eight cats, including Kofikat's surrogate mother.
The cloning of Copycat was done after pigs and goats and of course sheep had already been born in this way - the first of which was Dolly, who was cloned in 1996 (and died in her infancy in February 2003). The project in which the copycat was cloned was a scientific success that should not be taken lightly, but it seems that behind it was also an understanding of the tremendous potential inherent in selling the illusion of "re-creating" deceased pets. The sorrow associated with the death of dogs, cats (and particularly sympathetic parrots or iguanas) may be translated into dizzying business success.
Copycat was part of another project, the aim of which was to clone a mixed breed dog named Missy. The project was funded by the money of Missy's owners, who really wanted her to breed while she was alive so that she could have enough and play with herself before she died. They invested close to four million dollars for this purpose.
When the copycat cat was born, Missy was still alive, but the experiments to clone the dog did not go well and Missy died in July 2002, aged 15. In an interview with the "Washington Post", after her death, the family members announced that they would transfer another few million dollars to continue the project. In the meantime, they said, they will go to an animal shelter and take a new puppy from there, as many dog owners do after the death of their beloved dog.
One thing is common to the cloning of a copycat and the failed attempts to clone Misi: in both cases loud voices were heard against the act itself, not only from those who see it as an interference in the act of Genesis, but rather from representatives of associations working for animals. These claim that in a world filled to the brim with homeless cats and dogs, there is no room to produce more puppies.
This year, the company that successfully cloned Rainbow, in the form of a copycat, announced that it will clone additional cats for $50. In the future, they hope, such a clone will cost much less, perhaps "only" two thousand dollars.
The way back to nature
By David Ref
The population of domesticated cats is divided into several groups: cats that spend their entire lives within the walls of the house and leave their familiar enclosure only for visits to the veterinarian; Domestic cats that spend part of their time outside - those that return to their homes, sleep and eat in them, but often also feed outside from leftover waste or hunting; Stray cats, which feed mainly on leftover food and waste left by humans and hunters. And there is another group: cats that have returned, against their will, "to nature" and are forced to hunt in order to survive. There are also twilight zones between these groups.
"Nature", for that matter, may be an abandoned industrial area or a non-urban area, similar to the habitat of wild cats. Cats living in such areas go through an interesting process called feralization, which means returning to the wild.
Cats show a surprising ability to adapt even to conditions that many generations have not lived in. Feral cats must hunt for their food and exhibit social traits and behaviors similar to those exhibited by individuals of the wild cat.
Cats that have become feral are found almost everywhere where domestic cats have been raised in recent centuries, in cities and agricultural settlements, but also in areas far from human settlements - in forests or islands where there are no permanent human settlements. According to estimates, about 60 million such cats roam the US alone, but this estimate does not include a clear distinction between feral cats and street cats.
In the 80s, a study was done in Sweden on a mixed population of domestic and feral cats. The study, which followed 37 cats, showed that the territorial area marked by feral cats was approximately four times larger than the area marked by female domestic cats; The time the wild females spent hunting was, as expected, twice the time spent by the domestic cats.
Among the males tested, the territorial area marked by the feral cats was double that of the domestic cats. It was also proven that domestic cats showed signs of acceptance of feral cats.
The rapid spread of domestic cats, even in areas where they did not live in the recent past, sometimes led to a significant reduction in rodent populations, which humans consider pests. But in some places the feral cats themselves are seen as pests, and the debate about the way they should be treated is related to the debate about the future of street cats.
There are no official data on the number of feral cats in Israel. In his book "Russian Novel" Meir Shalev describes one of them, Bulgakov, Riva Margolis's toy cat, "who went wild and became the most horrifying killer seen in our fields". The cat, explains one of Shalu's heroes, kills for pleasure and not for hunger, "under the bad influence of humans".
Although they would certainly object to the demonization of feral cats, many researchers believe that their population should indeed be reduced in the wild areas of Israel. The cats are skilled predators, and their invasion of areas where they did not live before sometimes makes a name for the wild populations, both in the world and in Israel.
House cats believe in free love
By David Ref
Unlike wild cats, domestic cats are ready to mate with any random male
The image of the big city, especially among those who do not live there, is that of a volume that offers a variety of sexual possibilities. A study published in 2000 in the magazine "Aggressive Behavior" proves that this is definitely true for domestic cats.
Three researchers examined the sexual choice strategies of cats, females and males, in an urban environment. In such an environment, social groups were formed, a phenomenon foreign to most cat species. In nature, the wild cat is a territorial animal. In the territory where one male lives, there are two or three females, who may mate with the male and raise their joint offspring. Studies that dealt with the European wild cat showed that there is an indirect struggle between the males for the females. The dominant males - the big, the strong and the young - take over a "successful" territory where food and water are supplied and thus they also win the females.
The study on the street cat population took place in Rome, in Piazza Vittorio Emanuele, in an antiquities area which at the time was fenced off and few people entered it. The researchers focused on 19 males and 15 females that were observed mating at least once in the 112 days of the study. There was plenty of food there, from leftovers from the nearby market and food that people shared.
The researchers looked for females that showed signs of heat - typical howls, body parts rubbing against objects and rolling on the ground. The times when females refused to mate with the males and the times when they agreed were counted and parameters related to the mating itself were recorded.
The results of the study showed a behavior different from that of cats in the wild: most females mated with several males in one estrus period. Some of them mated with all the sexually active males in the group, others mated with most of the males and there were cats that mated with less than half of the males. The researchers claim that the females of the domestic cat do not exercise quality selection on the males with whom they mate, but, sometimes, random selection. As for the males - most of them tried to mate with several females.
The disadvantage of multiple matings is an increased risk of disease and injury. The possible advantage is greater genetic diversity between the different offspring in each litter and creating a greater chance of survival in a changing environment.
The study offers two theories to explain its results: the first holds that the social changes among the domesticated cats occurred too quickly in social-evolutionary terms, and the female cats have not yet adapted to selective behavior. According to a second opinion, selection does occur, but it focuses on the "competition" between the sperm cells of the different males, and on the competition that takes place on the genetic level, according to which the offspring that are better adapted to the environmental conditions survive - that is, the offspring of a certain male among the males that mated with the same female.
By David Ref
The chance of a cat whose owner smokes getting cancer is 2.4 times greater
Caution! Smoking kills Mitzi
In the USA, the warning sentences on the cigarette packs are not enough to warn of the harms of smoking. More persuasive means were also used to convey the message - photographic evidence of the harms of smoking to humans. However, a warning that "smoking kills your pet!" It is not yet printed on the cigarette packages, although research on the subject shows that the statement is definitely correct.
Researchers from the School of Veterinary Medicine at Tufts University in Massachusetts, in collaboration with researchers from the University of Massachusetts, examined the correlation between the appearance of lymphoma in cats and their exposure to cigarette smoke and other tobacco products. In the study, the disease reports of 80 cats that were treated at the Tufts University Veterinary Hospital in the years 2000-1993 and diagnosed with lymphoma were examined. Lymphoma is a fatal disease, which usually occurs in cats 10 years of age and older.
Detailed questionnaires were sent to the cat owners. They were asked to answer questions concerning the two years preceding the diagnosis of the disease in their cat. to refer to the characteristics of the cat (gender, length of its hair), its living environment (city or village) and its lifestyle (lives at home or tends to wander outside). They were also asked to provide details about their smoking habits, if they smoke.
The findings, published two years ago in "The American Journal of Epidemiology", show a clear correlation between passive smoking of cats and the development of cancer in the lymph nodes in their body.
The importance of the research is not only in understanding the health danger posed to cats from passive smoking, but also in the histological similarity (tissue structure) between feline lymphoma and cancerous lymphoma in humans. The study of the causes of lymphoma in cats may help to better understand the development of cancer in humans.
The study focused on 33 cats whose owners smoke regularly at home. According to the study, the chances of cats exposed to cigarette smoke to develop lymphoma are on average 2.4 times greater than the chance that the disease will develop in cats not exposed to smoke. The effect of cigarette smoke is also derived from the duration of exposure - the risk of lymphoma in cats that have been exposed to smoke for five years or more is 3.2 times that of cats that live in smoke-free homes.
A cat living in a house with one smoker is 1.9 times more likely to develop lymphoma. In a house where there are two smokers, the chances of getting sick jump according to 4.1. The researchers also isolated the component of the number of cigarettes the cat's owner smokes and the concentration of tobacco. It turned out that in a house where we smoked a pack of cigarettes a day or more, the cat's chances of getting lymphoma increased 3.3 times.
The researchers believe that some of the ingredients released into the air when smoking tobacco products have a carcinogenic (cancer-causing) effect on the tissues of the lymph nodes in cats. They point to a similarity between cats and children, who, like the cats, spend a relatively long time at home (compared to the smokers themselves), and like the pets, play with objects that may have had substances released during smoking stuck to them.
85% that the cat will not be infected with feline AIDS
By David Ref
There is a vaccine for this disease. In Israel he is not popular
Janet Yamamoto, a young researcher from the University of California, isolated the FIV virus (Feline Immuno-deficiency Virus) in 1986. FIV, a distant relative of the HIV virus, causes a disease that most veterinarians were unaware of its existence in the mid-XNUMXs - "AIDS cats".
FIV is found in the blood and saliva of an infected domesticated cat (similar viruses have been discovered in other felines such as lions and cheetahs) and is transmitted to other cats through a bite; The disease is rarely transmitted from a cat to her kittens. It is important to clarify that the fear of people who are frightened, because of the name "cat AIDS", that the disease is also transmitted to humans is baseless.
After infection, the virus travels in the bloodstream to the lymph nodes, where it penetrates white blood cells and replicates itself. The new viruses travel with the blood to the other lymph nodes in the body and multiply rapidly (this is manifested by a temporary enlargement of the glands and sometimes fever and anemia).
The next stage, which may last months or years, is imperceptible. But it is not a static phase. In the sick cat's body, the number of white blood cells is constantly decreasing, and thus its defense system against bacteria, fungi, viruses and other parasites is severely damaged. When immune failure appears (a stage called FAIDS, similar to AIDS in humans), that is, a collapse of the immune system, most cats have a short lifespan of a few months.
Many of the owners of cats suffering from FIV only discover this when their cat is suffering from another disease and is brought to a medical examination, where a carrier test for the virus is conducted. The disadvantage of the test is that if not enough time has passed since the infection, a false negative answer may be obtained.
The disease is twice as common in males, for the simple reason that males (especially not neutered) are more involved in fights and are more injured. As a rule, in a cat with a pleasant temperament, who does not often leave the house, the risk of contracting FIV is extremely low.
For reasons that have not yet been sufficiently clarified, the incidence of the disease varies greatly from place to place. In Israel there are no exact data on the rate of sick cats. According to surveys conducted in recent years, in France about 11% of cats have the disease, in England 6%, in Switzerland 0.7%, in Spain 8.3%, and in Japan, for unknown reasons, about 44%. In the US, about 2% of cats carry the virus, it has been proven that in populations where several sick cats were found, the rate of infection increased in a short time and reached about 15% or more.
16 years after she isolated the FIV virus, Yamamoto managed to develop a first-of-its-kind vaccine for the disease it causes. The vaccine she developed consists of the two main strains of the virus and has been found to be effective in about 85% of cases. In 2002 it was approved for use in the USA. You can get the vaccine at veterinary clinics in Israel, but according to veterinarian Dr. Eitan Kreiner, "the demand is extremely low, probably because the disease is not common in Israel."
The vaccine has a distinct disadvantage. Because it consists of a killed virus, which stimulates the production of antibodies, the carrier test result of a vaccinated cat will always be positive, whether or not it is infected with the virus.
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