Size
Full grown goliath tarantulas can be 12 inches (or 30.5 centimeters) in diameter (from the tip of one leg to the tip of its pair). They can weigh up to 2.5 ounces (or 70 grams). Their fangs can average in length from 0.4 to 1 inch (or 1 to 2.5 cm). Sacks full of eggs lain by females average 1 inch (3 cm) wide.
Defense
According to the Shedd Aquarium, goliath tarantulas are quite aggressive but still have ways to defend themselves. They are venomous, but the venom is about as bad a bee sting to a person. Unless the person is allergic to bee stings, there's no chance of dying. Goliath tarantulas can also hiss to startle attackers by rubbing their hind legs together. If that's not enough, they can fling the barbed hairs on their legs at attackers. Although not lethal, the hairs are very irritating.
Reproduction
Mating in goliath tarantulas is a risky business for the male because the larger females have a tendency to eat the males. They reach sexual maturity when they are about 2 to 3 years old. After mating, females lay silk pouches full of a clutch of eggs. There can be 100 to 400 eggs in a pouch that hatch an average of 60 days later. The female takes no part in raising the young.
Lifespan
Females live far longer than the males, mostly due to the females mistaking their mates for prey. Mating also seems to take a lot of energy out of the males. They only live to be 6 years old, while females can live up to 25 years old. Goliath tarantula males or females rarely reach old age due to being hunted as a food source by the indigenous peoples of South America.
Fun Fact
Goliath tarantulas, like other species of tarantulas, do not spin webs. They rely on surprise when capturing their prey. They will hunt like jumping spiders or like burrow spiders and wait for the vibrations of passing prey in order to alert them when to pounce. They bite to inject venom, which paralyzes the prey. They hardly ever eat birds and seem to prefer mice, frogs and insects.