Classification– Spiders and scorpions are arachnids. Each has two main body segments. Each has four pairs of walking legs and appendages near the mouth called chelicerae.

Diet- Insects such as crickets and mealworms; occasionally small rodents (“pinkie mice”). Prey Items must be “gut loaded” for 1-2 days in order to provide adequate nutrition. Offer water directly or by misting cage.

Respiratory– Breathe through book lungs: thin folds of cuticle projecting into the body cavity. These folds allow gas exchange between the atmosphere and the blood. Sometimes air must pass through a spiracle on the body surface to reach the book lung. Most arachnids have several pairs of book lungs.

Digestive– Simple digestive tract. Pet spiders and scorpions are both able chew food in order to consume it, however spiders generally also have the ability to predigest food by venom injection.

Reproductive- Pet spiders typically lay eggs while scorpions generally bare live young. Both practice internal fertilization of eggs. Both exhibit maternal care of egg sacs or very young offspring.

Nervous- Have several pair of eyes, yet poor vision. Rely heavily on sense of vibration.

Integument- Exoskeleton composed of chitin. Must molt old epidermis in order to grow larger.

Selected Diseases

Ectoparasites- Most pet spiders and scorpions are susceptible to mites. These can be removed by using gas anesthesia, then gently brushing sleepy mites off of the patient. Never use insecticides.

Baldness – Nervous spiders may brush urticarial hairs off of abdomen as a defense mechanism. These will reappear with the next molt unless spider has reached full size.

Missing Limbs- Legs are sometimes broken or lost due to trauma. The hole in the exoskeleton must be patched with surgical adhesive to avoid fatal blood loss. This may require anesthesia. Limbs usually regrow with successive molts.

Abdominal Rupture- If dropped, arachnids may suffer a split in the body wall. This defect can result in fatal blood loss. The injury should be sutured or repaired with tissue adhesive under general anesthesia. Blood loss should be compensated for by fluid injection. Antibiotics may be administered. In spite of a good repair, internal injuries may be present.

Molting Problems– “Dysecdysis” can be prevented by providing adequate humidity in the cage environment. Treatment involves sterile fluid injection and increasing humidity. Do not attempt to help your pet arachnid molt by pulling on shed portion; loss of limbs will likely occur.