This Golden Orb Weaver probably died soon after producing this sac full of eggs.
The vast majority of spiders never reach maturity. Most will end up as lunch for birds, lizards, other spiders or some other kind of predators, or else die in any of a seemingly limitless number of ways long before they grow up. But in the case of the lucky ones that do live to maturity, how long can they survive?
How long a spider lives is controlled very much by what kind of spider it is. Some (the modern types of spiders) have short lives and others (the primitive types) can live for several years.
Some spiders fall into a group called the mygalomorphs. Mygalomorphs haven’t changed much since very primitive times. They tend to be big, hairy, heavy-bodied, short-legged spiders. This group includes Funnel-web Spiders and Mouse Spiders. Mygalomorphs are different from the other kinds of spiders (called araneomorphs) because their fangs point down.
Mygalomorphs can live for a long time. They might take 12 years just to reach to maturity and then live for another 8 years after that.
The Deinopis Spider which made this egg sac had vanished and probably died when this photo was taken, meaning that the spiderlings would need to look after themselves after hatching.
By comparison, araneomorphs have fangs pointing sideways towards each other. Because they point towards each other they’re able to bite with a very efficient pinching action that would be the envy of the mygalomorphs. So, that’s one difference, but another difference is that araneomorphs live shorter lives.
For example, in temperate regions your typical araneomorph spider will live for about a year. It hatches out of its egg in spring, grows up in the warmer months and reaches maturity in summer or perhaps autumn. Towards the end of those warmer months it produces eggs and dies, leaving those eggs behind to start the next generation.
Araneomorphs include Huntsman Spiders, orb-web-producing spiders like Nephila and St Andrew’s Cross Spiders and most of the other spiders you’re likely to see around your house.
The mygalomorph spider (1) has fangs which can only swing down. The araneomorph (2) has fangs which are able to cross over into a pinching action. Mygalomorphs live longer than araneomorphs.
If you’re a male spider, then chances are you’re not going to live as long as your sisters. Male spiders tend to mate soon after reaching maturity and then die soon after that. In the case of the mygalomorphs, that can cut many years off their life.
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