We know that humans have internal clocks. That is an undisputed fact. It is not a very precise clock and so we refine it with timekeepers. It is plausible to suggest, and science supports this, that domestic cats also have an internal clock. It is the feline’s internal clock combined with their circadian rhythm and further combined with the rhythms and habits of their life which intermixes with those of their human caregiver which allow them to know with a considerable degree of accuracy when their owner is about to come home.
In October 2018, I wrote an article about the domestic cat’s internal clock. It was based on a study carried out in America at Northwestern University on mice 😊. The lead scientist and author of the report on the experiment said that a mouse’s brain has an “internal sense of time”. They use timing cells in a part of the brain called the medial entorhinal cortex (MEC) which is located in the temporal lobe and which is associated with memory and navigation. This is not the only research study which suggests that mammals including cats have internal clocks.
Further work is required on the feline internal clock. It is early days in this research based upon my research on the topic. But it is plausible to suggest that domestic cats have an internal clock much like that which benefits humans.
This is supported by another study titled “Circadian rhythm of intraocular pressure in cats”. The pressure inside the eye of cats and people various throughout the day. The variation is rhythmical and is synchronised with daytime and nighttime. It was found that the intraocular pressure in cats maintained this rhythm even under persistent darkness which suggested “some level of endogenous circadian control”. The word “endogenous” means having an internal cause or origin. I therefore interpret that phrase as meaning that cats have an internal clock which helps to control their circadian rhythms.
Cats have a circadian rhythm (source: National Library of Medicine, Biotech Information). Domestic cats can be active in the day and night but favour crepuscular activity (dawn and dusk) and prefer night to day. Their motivation to be active at these times comes from their internal circadian rhythm.
Light and darkness is the best-known environmental way that cats develop a circadian rhythm. Cats’ activity falls into synchronisation with daytime and nighttime. A further study found that cats generate internally timekeeping which dictates when they should be active. In my view, this further supports the cat’s internal clock.
Rhythms and habits in the human home
The life of a domestic cat automatically intermixes with the life of their human caregiver and in doing that the cat’s daily rhythms and habits fall into synchronisation with that of their human caregiver. This inevitably leads to moments in the 24-hour cycle when cats perform certain functions. In the instance of a person coming home from work a cat will not only use their internal clock to gauge the moment when they arrive but also rely on previous rhythms and habits to wait by the front door for their owner’s arrival.
In my view, it is a combination of the above factors working together which allows a cat to wait at the front door or window with a reasonable amount of precision for the arrival of their caregiver.
There are some more articles on crepuscular activity below.