Scarabaeidae

The Scarabaeidae family, commonly known as scarabs or scarab beetles, includes more than 35,000 species found across the globe. Its classification has shifted considerably over time; some groups once considered subfamilies are now treated as separate families (such as Bolboceratidae, Geotrupidae, Glaresidae, Glaphyridae, Hybosoridae, Ochodaeidae, and Pleocomidae), while others have been downgraded. The subfamilies listed here follow the 2023 Catalogue of Life.

These beetles have sturdy, stout bodies. Most are brown or black, but many daytime-active species display bright, metallic colors. Their size ranges from 1.5 mm to 160 mm (0.059 to 6.3 inches). The antennae appear knobbed, but the segments that form the head are actually flattened into plates called lamellae, which are usually held together in a ball. When tracking a scent, the beetle fans these lamellae out like leaves to detect odors.

Many scarabs are burrowers, with legs adapted for digging. In certain groups, males (and sometimes females) grow prominent horns on the head or pronotum to compete for mates or resources. The largest known fossil scarabaeid is *Oryctoantiquus borealis*, measuring 50 mm (2.0 inches) long.

The larvae, known as grubs, are C-shaped and pale yellow or white. Most adult beetles are nocturnal, though flower chafers (Cetoniinae) and many leaf chafers (Rutelinae) are active during the day. Grubs typically live underground or under debris, avoiding sunlight. Many scarabs are scavengers, recycling dung, carrion, or decaying plant matter. Others, like the Japanese beetle, feed on plants and can damage crops and vegetation.

Well-known members of Scarabaeidae include Japanese beetles, dung beetles, June beetles, rose chafers (Australian, European, and North American), rhinoceros beetles, Hercules beetles, and Goliath beetles. Several species have structurally colored shells that act as left-handed circular polarizers—the first example of circular polarization discovered in nature.

In Ancient Egypt, the dung beetle *Scarabaeus sacer* (formerly *Ateuchus sacer*) was considered sacred. Amulets depicting this beetle were traded throughout the Mediterranean region.