“This paper points out to a possibility that the lexema cat [mačka in Serbian language] originated from the basis of mat- (in Serbian language: mati, majka, in English language: mom, mother): the motivation basis for the both expression/word for cat/litter (in Serbian language: mačka/kot) could be connected with a representation of female genitals (womb, in Sebian language: materica), birthing, understood here as “expulsion”, and “unfold” of the large number of offspring.”
See: Why Do First Kittens End Up Down the Drain? An Iconic Meaning of the Lexema Cat and Litter (II) , Bulletitin of the Institute of Ethnography SASA, Glasnik Etnografskog instituta SANU, 2010 Volume 58, Issue 2, Pages: 131-145.
The full text : may be found here (Note: mainly in Serbian)
The photo : shows Dorty silikonski posip (3,8) cat latter, available from Petbox.rs, Subotica, Serbia.