It's only worms

The menagerie that is Pirkei Avot features no fewer than three different species of worm -- the rimah, the tole'ah and the shamir. One does not appear in Tanach at all. That is the shamir, which gets a name-check at Avot 5:8. This worm, whose natural habitat is the Talmud and midrash, is traditionally taken to have been employed in the construction of the First Temple, where the use of metal cutting tools was prohibited because of their affinity with weapons of war. Until recently the existence of this little rock-splitting worm was regarded as being far-fetched, the shamir being the stuff of myth and legend. However, discovery in the Philippines of the shipworm lithoredo abatanica has changed all that. Here is a tiny creature that actually burrows into stone and digests it, excreting it in the form of sand. Strictly speaking, while lithoredo (right) may look like a worm, it is actually a bivalve of the genus teredinidae. These species bore into wood and stone but not, it seems, into us.

Of more immediate concern to humans are the rimah (Avot 2:8, 3:1, 4:4) and the tole'ah (Avot 3:1). These are more conventional worms that dine upon corpses. The precise difference between them is unclear. It may be that the rimah burrows into the body from outside, while the tole'ah burrows out of the body from within (see Rabbi Yitzchak Zoller, cited in the compendium Mishnat Avot). The general function of the references to worms is essentially to remind us to be humble: however important we are (or, more usually, think we are) in our lifetimes, we all end up on the à la carte menu of miserable little creatures that are synonymous with lowliness and with being of little worth. 

It has been argued that worms play an additional role in Avot, this being to threaten that they will make a meal of the wicked, causing great pain in the process. There is a considerable body of rabbinic discussion on whether the dead feel anything after they have died, on the sharpness of worms’ teeth and on their ability to inflict pain (see e.g. Berachot 18b, Shabbat 13b and the discussion in Baruch She’amar al HaSiddur at Avot 2:7). Suffice it to say that, while these discussions are fascinating, they are something of a distraction. This is because there are no worms that possess teeth--a fact that would quite likely have been known to the sages of the Mishnah, who were no mean anatomists.

The reason why I felt it appropriate to mention this point now is that there have recently been a number of articles and news items concerning worms' teeth (see e.g. "Worm’s teeth conceal odd mineral material", here; "Bloodworms Make Their Teeth From Metal And Now We Know How", here; "Scientists discover how bloodworms make unique copper teeth", here). These headlines are misleading and do not disprove the rule that worms have no teeth. The bloodworm glycera (left), which is carnivorous, feeds by extending a large proboscis that bears four hollow jaws--and it is these jaws, mistakenly called "teeth", which contain copper. 

While the bite of the bloodworm is painful even to a human, because it injects venom when it clamps its jaws upon its victim, we humans can take comfort from the fact that they, in turn, are eaten by other worms.