Biology and behaviour
Theraphosa blondi fangs © G Beccaloni
Biology
Although called a ‘bird-eater’, Theraphosa blondi doesn’t normally eat birds.
It usually feeds on insects such as crickets and beetles, but it will also eat small mammals, frogs and reptiles.
Like most spiders, Theraphosa blondi has poor eyesight so it relies mainly on sensing ground vibrations.
It will rush out of its silk-lined burrow when it detects potential prey, and subdues it by injecting it with venom though its 20mm long fangs.
Although very formidable looking, a bite from this species is apparently no worse than a wasp sting.
An adult female lays 50–150 eggs in a huge silk egg sac (approximately 30mm in diameter).
She carries this around with her to protect her offspring.
After around 2 months, the spiderlings emerge. They may live communally in their mother’s burrow until they are about a third grown, and then they disperse.
Youngsters take around 2.5–3 years to mature and females can live up to 20 years.
Males have a lifespan of only 3–6 years, dying soon after maturity.
Like other tarantulas, Theraphosa blondi continues to moult into adulthood which enables it to regenerate any limbs that have been lost or damaged.
Behaviour
A Theraphosa blondi is very capable of warning off potential predators. It does this in several ways:
- It may produce a hissing noise, by rubbing together the bristles on the first 2 pairs of legs and pedipalps (front appendages) - this is called stridulation.
- It can adopt a fearsome pose by throwing the first 2 pairs of legs back, opening and hinging back the fangs, so that it’s in a perfect position to inflict a bite.
- It can also flick urticating (irritating) hairs from its abdomen using the hind legs. These hairs are barbed at the tips, and can severely irritate the skin, nose and eyes of mammals, including humans - small mammals such as mice can die from such irritation.
- Adult females incorporate these urticating hairs into the silk surrounding their eggs, as a form of protection for the developing young.
