ויקרא, פרק י״א, פסוק כ׳

Flying insects represent a unique category of animal life, blending the ability to fly with an earthly, crawling movement. These creatures are typically agile and travel in large swarms. Commentators offer different perspectives on what precisely defines this group. One approach focuses on their physical size and low altitude, identifying them as thin, low-flying creatures that swarm over the earth, such as flies, wasps, mosquitoes, and locusts [רש״י]. Within the broader family of winged creatures, these are considered the lowest class [מזרחי]. However, another perspective rejects size as the defining factor, noting that small flying animals like bats are excluded from this category, while larger insects like certain locusts are included. Instead, this view defines the group by its posture and method of movement. While a typical bird walks upright on two legs with its head held high, these swarming creatures walk on four legs, keeping their bodies low to the ground and their heads tilted downward [רמב״ן, ביאור ישר]. Furthermore, they run and move with much greater speed than two-legged animals and naturally gather in massive swarms [העמק דבר, רד״צ הופמן].

The description of these creatures as walking on four legs presents a biological question, as many flying insects, such as bees, actually possess six legs [רשב״ם]. Several explanations address this discrepancy. From a functional standpoint, two of the six limbs often serve as hands used for digging, leaping, hunting, or grasping, leaving only four legs dedicated to standard walking [ביאור שטיינזלץ, ברכת אשר על התורה]. For example, a locust uses its two specialized hind legs for jumping, while the remaining four are used for walking [רד״צ הופמן]. Alternatively, the number four might not be a strict mathematical count, but rather a way to emphasize that these creatures have more than two legs, which is the fundamental distinction between them and ordinary birds [רש״ר הירש]. It may also simply be a common human idiom used to describe horizontal, crawling movement [רד״צ הופמן]. Interestingly, an insect possessing exactly five legs is actually considered pure and falls outside of this prohibition altogether [רמב״ן].

The rationale behind avoiding these insects is tied to their anatomy. A multitude of legs indicates internal weakness and an overabundance of coarse, earthly matter within their bodies. This physiological makeup renders them un-nutritious and unfit for human consumption [רלב״ג]. The severe terminology used to describe them as detestable highlights the strict nature of the restriction, which forbids not only consuming the insect itself but also any juices or broths derived from it [אדרת אליהו]. The instruction to avoid these swarming creatures serves as a positive Commandment to distance oneself from them, while the specific punishment for eating them is derived from other warnings found in the book of Deuteronomy [רמב״ן]. Finally, while locusts generally belong to this forbidden group [העמק דבר], certain specific species are permitted for food. Today, however, the precise tradition required to identify these permissible species has been preserved only within specific groups, such as the Yemenite Jewish community [חומש קה״ת].