Many people have always believed that animals always catch the preys that are young, old or sick, for it would be difficult for those prey to escape a predator's hold.For years, there were no scientists who could prove this fact.But latest research by French scientists in Paris, France, has proved that it is true. The scientists studied the hunting habits of cats. And they studied the health of birds that were killed by cats with those killed in accidents. They made a study of spleen(肾脏) which show its good health.
The scientists chose the spleen because of a special reason. Birds that are healthy have larger sized spleens than those which keep getting infections. The spleen helps the birds to fight disease. So from the size of the spleen the French scientists could find out if the birds killed by cats were healthy or sickly.
They examined more than 500 birds and made very interesting discoveries. The spleens of birds killed by cats were much smaller than those killed in accidents. It means that they were not very healthy.
Also most of the birds killed by the cats were young. Of those that died in accidents, half were young and half were adult. So while it is true that the young and the sickly birds are at a greater danger of becoming a cat's lunch or dinner, old birds are able to take care of themselves.
