For the first several weeks, kittens cannot urinate or defecate without being stimulated by their mother.[6] They also cannot regulate their body temperature for the first three weeks, so kittens born in temperatures less than 27 °C (81 °F) can die from hypothermia if their mother does not keep them warm.[7] The mother's milk is very important for the kittens' nutrition and proper growth. This milk transfers antibodies to the kittens, which helps protect them against infectious disease.[8] Newborn kittens are unable to produce concentrated urine, and so have a very high requirement for fluids.[9] Kittens open their eyes about seven to ten days after birth. At first, the retina is poorly developed and vision is poor. Kittens cannot see as well as adult cats until about ten weeks after birth.[10]

Female cats are seasonally polyestrous, which means they may have many periods of heat over the course of a year, the season beginning in spring and ending in late autumn. Heat periods occur about every two weeks and last about 4 to 7 days.[178] Multiple males will be attracted to a female in heat. The males will fight over her, and the victor wins the right to mate. At first, the female rejects the male, but eventually the female allows the male to mate. The female utters a loud yowl as the male pulls out of her because a male cat's penis has a band of about 120–150 backwards-pointing penile spines, which are about 1 mm long; upon withdrawal of the penis, the spines rake the walls of the female's vagina, which acts to induce ovulation. This act also occurs to clear the vagina of other sperm in the context of a second (or more) mating, thus giving the later males a larger chance of conception.[179]

Matthew J. Hanson, the creator of Magical Kitties Save the Day, has written RPG material for Kobold Press, Green Ronin Publishing, Dragon and Dungeon Magazines, EN Publishing, Expeditious Retreat Press and more. He also runs a small publishing company called Sneak Attack Press which produces both licensed work, like the silver ENnie Award-winning Broken Earth setting, and original RPGs, like Abstract Dungeon. He lives in Minneapolis with his wife, two cats, and 18-month old son. His son's first word was, in fact, "kitty."
Back in the present, after Gus exits, Skimbleshanks is seen sleeping in the corner ("Skimbleshanks: The Railway Cat"). He is the cat who is unofficially in charge of the night train to Glasgow. Skimbleshanks is considered vital to the rail operations, as without him "the train can't start". Within his song, a whole steam train engine is assembled out of objects in the junkyard.
An event called the Jellicle Ball was referenced by Eliot in the poem "The Song of the Jellicles", while a cat version of heaven known as the Heaviside Layer was mentioned in one of his unpublished poems. Nunn expanded on these concepts by conceiving the Jellicle Ball as an annual ritual in which the cats vie to be chosen to ascend to the Heaviside Layer, thus giving the characters a reason to gather and sing about themselves in the musical. He also added the element of rebirth as a play on the idea that cats have nine lives.[1]
The musical's fantasy setting and disregard for verisimilitude allowed for groundbreaking experimentations in lighting and audio technology. The original London and Broadway productions featured David Hersey's pioneering use of automated lighting to produce kaleidoscopic landscapes and complicated optical effects. Hersey also used light in an "architectural manner", with fast-changing configurations to spotlight different performers in rapid succession. This dynamic shifting of the audience's perspective created an effect similar to that of fast cutting in film editing.[16] The original London production of Cats was also the first known instance in which an entire cast was individually outfitted with radio microphones.[327] The departure from shared ambient microphones meant that the show did not have to depend on the acoustics and architectural design of the theatrical venue, and enabled the sound designer to achieve cinematic levels of sound amplification and studio-quality audio in live theatre.[328] This practice transformed sound design and has since become the norm in live theatre.[327]
On islands, birds can contribute as much as 60% of a cat's diet.[226] In nearly all cases, however, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances, eradication of cats has caused a 'mesopredator release' effect;[227] where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey. Domestic cats are, however, known to be a contributing factor to the decline of many species, a factor that has ultimately led, in some cases, to extinction. The South Island piopio, Chatham rail,[224] and the New Zealand merganser[228] are a few from a long list, with the most extreme case being the flightless Lyall's wren, which was driven to extinction only a few years after its discovery.[229][230]

Female domestic cats can have kittens from spring to late autumn, with litter sizes ranging from two to five kittens.[9] Domestic cats can be bred and shown as registered pedigreed cats, a hobby known as cat fancy. Failure to control the breeding of pet cats by spaying and neutering, as well as abandonment of pets, has resulted in large numbers of feral cats worldwide, contributing to the extinction of entire bird species, and evoking population control.[10]