Ontogeny

How does a cat's purr develop?

To explore how the behavior of purring develops within a cat’s lifetime it is necessary to first examine when purring begins and whether it changes over the course of the animal’s development. Purring is observed in kittens within the first few days of birth [14], possibly even beginning on the second day [15]. Kittens mainly purr when suckling from the mother [8, 14]. As an adult, purring is observed frequently, especially involving contact with another cat or person, such as petting or rubbing against furniture [14]. 

A study in 1991 measured the fundamental frequency of purring for 10 domestic cats between the ages of 10 weeks and 8 years [10]. In these 10 animals, the fundamental frequency of purring was measured to be 26.3 Hz +/- 1.95 SD, and the total observed range was 23 to 31 Hz. The authors also measured the chest circumference, nose to rump length, weight, and sex of each animal and found that the purring frequency was not correlated with weight, age or any of the other measured variables. This strongly suggests that the purring behavior does not change over time and is therefore not substantially developmentally regulated. To confirm this, the authors recorded the fundamental frequency for one cat at various time points from the age of 12 weeks to 3 years and found that the fundamental frequency did not change. Similarly, it has also been shown that in different Felidae species such as pumas, oncillas and domestic cats, frequency in individual animals remains constant as the animal ages [5]. Overall, this is very strong evidence that purring is not developmentally regulated. The fact that development does not affect purring suggests that it is a completely instinctual behavior, encoded for in the genome and requiring no learning whatsoever.

Because purring is primarily used by cats in social situations, either with a human or another cat, Turner and Bateson, the authors of a book on the biology of the domestic cat, have wondered whether the absence of purring would affect cat-cat or cat-human relationships [14]. Little has been done to examine this question. Turner and Bateson suggest that, as a first step, one could look at the natural variation present in domestic cats regarding the amount of purring [14].

While it is traditionally thought that roaring cats like the lion, tiger, leopard, and jaguar cannot purr, R. F. Ewer hypothesized that these species can, in fact, purr, but only as juveniles [5].