The animal which most biologists call “daddy-long-legs”, is a spider, Pholcus phalangioides, which belongs to the spider family Pholcidae, order Araneida, class Arachnida. Pholcid spiders are araneomorph spiders which kill and digest their prey using venom. However there is no scientific basis for the urban myth that daddy-long-legs are the most venomous, poisonous or toxic spiders in the world. Daddy-long-legs spiders have venom glands and fangs but their tiny fangs are fused at the base and it is rare for human to be bitten as their jaws do not open very wide.
Their venom has not been studied in detail. As far as Dr Mike Gray (senior arachnologist at the Australian Museum) knows, there is no evidence in the scientific literature to suggest that the venom of daddy-long-legs could harm humans. There is also not much scientific evidence to suggest whether or not they can bite humans, this seems to be part of the myth as well!! However daddy-long-legs kill and eat other spiders, including Redback Spiders whose venom CAN be fatal to humans. Perhaps this is the origin of the rumour that daddy-long-legs are the most venomous spiders in the world.
It might be argued that if they can kill a deadly spider, they must be even more deadly themselves, but daddy-long-legs only need to be quicker to bite, not more venomous. Keep scroling down for photos of the Opilione spiders also called Daddy Longlegs or Harvestmen spiders.
Daddy Longlegs (Pholcus phalangioides)
Daddy Long Legs -Harvestmen (Opiliones)
The other eight-legged invertebrates which are sometimes called “daddy-long-legs”, are members of the order Opiliones or Opilionida in the class Arachnida. Biologists generally call these animals ‘harvestmen’ (e.g. the CSIRO Handbook (ed. Ian Naumann) cited above).
Unlike spiders, they only have one part to their bodies and their bodies do not have a ‘waist’ and they do not produce silk; they normally have only one pair of eyes. They do not have venom glands or fangs, although they may produce noxious defence secretions.
Most harvestmen eat smaller invertebrates but some eat plant material and others feed on carcasses of dead mammals and birds.