Annabel Turnbull, of Green Island School, asks :-

How long do tarantulas live?

Simon Pollard, a spider biologist at Canterbury Museum, responded.

About 800 species of big hairy spiders belonging to the family Theraphosidae are commonly called tarantulas and they can be as big as dinner plates. This family is part of a primitive group of spiders called mygalomorphs which have been around for over 300 million years and have stocky bodies and downward pointing fangs. While New Zealand has a large number of native mygalomorphs, it does not have any theraphosids.

Tarantulas are very popular as pets in some countries and owners make sure they live a life of luxury with unlimited food and no predators. In these surroundings they can live for around twenty years and one elderly tarantula actually made it to 28 years old. Tarantulas take around four to seven years to become adults, and grow larger by regularly moulting, so their expanding bodies can fit into a new skin. While males stop moulting once they mature and tend to die a couple of years later, femalesmoult and grow as long as they live. I have seen a very well fed 25 cm long goliath bird-eating tarantula with an abdomen almost the size of a tennis ball. In the wild they are unlikely to get as fat or as old and probably die after a decade.

One common New Zealand mygalomorph spider, the tunnel web, looks like a small version of a tarantula. I gave a female to my uncle and aunt as a Christmas present and it lived in their bedroom in an aquarium fitted out as a spider home, for ten years. Another reason why my Christmas present and tarantulas live so long is their very slow metabolism. Except when they grab prey, they tend to stay still and are really the couch-potatoes of the spider world.