Average hours per day (American Time Use Survey) This term refers to the average number of hours spent in a 24-hour day (between 4 a.m. on the diary day and 4 a.m. on the interview day) doing a specified activity.
Usually a cats first season is somewhere between 4 and 10 months old with average age around six months. Siamese and Burmese cats are quite precocious and will often have their first season at 4 months of age.
Well, cats can reproduce starting around 6 months of age--give or take a few weeks--but at that age they would be teenage parents. Most cats reach adult proportions around a year old, but some breeds can take up to two years to fully mature. So that's the technical answer.