Drop spiders

Despite being called spiders, drop spiders are not in the order Araneae due to having only one body part and only six legs. They do, however, belong to the class Arachnida. The oldest known drop spider fossil dates to 200 million years ago and was found in what is now present day Australia. ^[1]

Morphology

Drop spiders are characterized by their large, almost spherical bodies, which can grow up to two feet in diameter, their stumpy orange and black striped legs, thick black fur, and large eyes, fangs, and mouth. Like face mites, drop spiders have no anus; unlike face mites, drop spiders regurgitate their waste and thus have a significantly longer lifespan, often reaching ten years of age. ^[2]

Behavior

Drop spiders are ambush predators and will sit in trees, waiting for prey to pass underneath. Once a suitable prey animal approaches, the drop spider will fall out of the tree mouth-first onto the animal.

Diet

Drop spiders are largely carnivorous. Plant matter has been found in drop spider feces although this is believed to have been unintentionally ingested by drop spiders as they fall through the forest. Over 400 species have been recorded as being the prey of drop spiders including mammals, birds, reptiles, amphibians, insects, and arachnids. 76% of the prey consumed by adult drop spiders consists of small to mid-sized mammals although on occasion large mammals such as adult red kangaroos have been taken as prey. Young drop spiders prefer to feed on large insects and arachnids. ^[3] There have been several unconfirmed reports of drop spiders feeding in humans although no concrete evidence has been found to support this. ^[4]

Range

Drop spiders are native to tropical Australia. A small population of drop spiders has become established in Florida where they pose a threat to native wildlife. It is speculated that another species of drop spider may be present in subterranean Antarctica although this has yet to be confirmed. ^[5]