All spiders produce venom. But three spiders present in New Zealand that bite humans and pets can cause significant harm.
Australian Redback & New Zealand Katipo:
- These are widow spiders, and the females have a neurotoxic venomous bite. The spiders only occur in some areas (beaches for Katipo, and urban pockets in Auckland, Tauranga, Gisborne, Hawke’s Bay and Central Otago for the Redback) in hidden crevices, but will bite if their web is disturbed.
- The severity of envenomation depends on several factors including size and age of the victim, and the amount of venom injected.
- Although the bite can be painful to humans, it usually causes just a local reaction. People with severe symptoms are administered antivenom.
- Cats are highly sensitive to bites, and will be in severe pain, with loud vocalisation, salivation and restlessness, vomiting, diarrhoea, muscle tremors and muscle and respiratory collapse. Without anti-venom, bites are usually fatal.
- Signs in dogs are less severe but may still include restlessness, pain, muscle cramps, abdominal rigidity and raised heart rate.
- Tissue damage local to the bite may be severe and wounds may take several months to heal. Fortunately, pet bites are extremely rare.
Australian Whitetail
- Whitetail spiders are vagrant hunters with a cyotoxic venom bite who seek out prey rather than spinning a web to capture it. Their preferred prey is other spiders — making them a disliked pest, as they hunt other beneficial native spiders.
- Human bites are fairly common and result in a local painful red mark, swelling and itchiness.
- There are many vets who have seen pet patients with severe tissue damage that they suspect have been caused by the whitetail. Even though initial damage may seem minimal, it can become quite serious quite quickly and owners are advised to act quickly if you suspect your pet has been bitten.
