The website Jewish Values Online asked me to answer the following question:
Is it wrong to light a yahrzeit candle or want a memorial service for a beloved dog?
It is healthy to desire to memorialize and respectfully remember a beloved companion animal, and it may be attractive to employ elements of the Jewish mourning customs to grieve the loss of a pet.
The mourning practices of Judaism are powerful, effective and wise, and they express utmost respect and recognition that those who die are vessels of a sacred soul for whom we shared a unique familial bond; they also address the unique pain and sorrow that accompanies the mourner over such a loss of life. For these reasons, using the tools of Jewish mourning is inappropriate for the death of an animal.
The idea to memorialize in a specifically Jewish way via a yahrtzeit candle and/or a similar memorial service is to conflate three matters:
1. the Jewish identity of the one who is grieving;
2. the Jewish customs associated with mourning the loss of a famiy member; and
3. the death of a non-human
Jewish mourning rituals are reserved for a Jew who loses a close family member (parent, spouse, sibling or child). In the same way it would be inappropriate for non-Jewish mourners to adopt Jewish mourning practices – because it is a misapplication of our sacred religious ritual that is specifically defined to exclusive circumstances – so, too, it is inappropriate to apply Jewish mourning practices to the death of a non-human life.
A core value of Judaism is the recognition of the intrinsic value of each human life because we believe that humans share qualities with Gd that are exclusive to these two beings. While the desired effect may be to elevate the worth of an animal's life by mourning it in a human way, in fact and in practice it denigrates the worth of human life. The death of a human family member and that of a companion animal are meant to be, and are, incomparable. To be clear – Jewish mourning is not about the level of love felt toward the object that is lost but is the recognition of the departure of a soul from our world – a soul that possessed unique, Gd-like qualities to transform the world whether or not those qualities were ever actualized.
To light a yahrtzeit candle on the anniversary of both the death of a parent and a pet is to place their cosmic worth on similar planes – though one who is Jewish may choose to do so the act is counter to Judaism.