Feathery Caterpillar

Pretty! Taken at night in Singapore forest.

Quote from en.wikipedia.org/wiki/Caterpil…

More aggressive self-defense measures are taken by some caterpillars. These measures include having spiny bristles or long fine hair-like setae with detachable tips that will irritate by lodging in the skin or mucous membranes.[3] However some birds (such as cuckoos) will swallow even the hairiest of caterpillars. Other caterpillars acquire toxins from their host plants that render them unpalatable to most of their predators. For instance, Ornate moth caterpillars utilize pyrrolizidine alkaloids that they obtain from their food plants to deter predators.[7] The most aggressive caterpillar defenses are bristles associated with venom glands. These bristles are called urticating hairs. A venom which is among the most potent defensive chemicals in any animal is produced by the South American silk moth genus Lonomia. Its venom is an anticoagulant powerful enough to cause a human to hemorrhage to death (See Lonomiasis).[8] This chemical is being investigated for potential medical applications. Most urticating hairs range in effect from mild irritation to dermatitis.

Plants contain toxins which protect them from herbivores, but some caterpillars have evolved countermeasures which enable them to eat the leaves of such toxic plants. In addition to being unaffected by the poison, the caterpillars sequester it in their body, making them highly toxic to predators. The chemicals are also carried on into the adult stages. These toxic species, such as the Cinnabar moth (Tyria jacobaeae) and monarch (Danaus plexippus) caterpillars, usually advertise themselves with the danger colors of red, yellow and black, often in bright stripes (see aposematism). Any predator that attempts to eat a caterpillar with an aggressive defense mechanism will learn and avoid future attempts.

Some caterpillars regurgitate acidic digestive juices at attacking enemies. Many papilionid larvae produce bad smells from extrudable glands called osmeteria.

Some caterpillars have long "whip-like" organs attached to the ends of their body. The caterpillar wiggles these organs to frighten away flies.[9] Some caterpillars can evade predators by using a silk line and dropping off from branches when disturbed. Many species thrash about violently when disturbed to scare away potential predators. One species (Amorpha juglandis) even makes high pitched whistles that can scare away birds.