The London production ran for 21 years and 8,949 performances, while the Broadway production ran for 18 years and 7,485 performances, making Cats the longest-running musical in both theatre districts for a number of years. As of 2019, it remains the sixth-longest-running West End show and the fourth-longest-running Broadway show. Cats has since been revived in the West End twice and on Broadway once. It has also been translated into multiple languages and performed around the world many times. Long-running foreign productions include a 15-year run at the Operettenhaus in Hamburg that played over 6,100 performances, as well as an ongoing run in a purpose-built theatre in Japan that has played over 10,000 performances since it opened in 1983.
Preformed vitamin A is required in the cat for retinal and reproductive health. Vitamin A is considered to be a fat-soluble vitamin and is seen as essential in a cat's diet. Normally, the conversion of beta-carotenes into vitamin A occurs in the intestine (more specifically the mucosal layer) of species, however cats lack the ability to undergo this process. Both the kidney and liver are contributors to the use of vitamin A in the body of the majority of species while the cats liver does not produce the enzyme Beta-carotene 15,15'-monooxygenase which converts the beta-carotene into retinol (vitamin A). To summarize: cats do not have high levels of this enzyme leading to the cleavage and oxidation of carotenoids not taking place.
Part of the kitten's immune system is the mucosal immune system, which is within the gastrointestinal tract. The mucosal immune system is largely responsible for coordinating proper immune responses by tolerating innocuous antigens and attacking foreign pathogens. In order to optimize kitten health and increase chances of survival, it is important to optimize the link between the gut-associated lymphoid tissue and the microbiota of the gastrointestinal tract. Lasting health and longevity can be accomplished partly through proper nutrition and establishing a healthy gut from birth through utilizing colostrum.
Cats are similar in anatomy to the other felid species, with a strong flexible body, quick reflexes, sharp teeth and retractable claws adapted to killing small prey. They are predators who are most active at dawn and dusk (crepuscular). Cats can hear sounds too faint or too high in frequency for human ears, such as those made by mice and other small animals. Compared to humans, they see better in the dark (they see in near total darkness) and have a better sense of smell, but poorer color vision. Cats, despite being solitary hunters, are a social species. Cat communication includes the use of vocalizations including meowing, purring, trilling, hissing, growling and grunting as well as cat-specific body language. Cats also communicate by secreting and perceiving pheromones.