Facts About Redback Spiders

Interesting Facts About Redback Spiders

Redback spiders (Latrodectus hasselti) are native of Australia and New Zealand. They belong to the family Family Theridiidae and are a close relative of the American black widow spider. Characterized by a black body with a bright red/ orange stripe on the top, redback spiders are known for eating their prey after paralyzing them. There are lot more fascinating facts on them. Read on to know more about redback spiders.

Venom and bite

Only female redback spiders’ venom is dangerous to humans. The victim will have a time of about 4 hours to get an antidote before the spider proves fatal. The pain sets in usually after an hour, hence, hence delaying the realization that you have been bitten.

The antivenom for the redback spider was invented in 1956. A redback spider bite is rarely fatal to humans provided that proper medical attention is given. The symptoms of being bitten by a redback spider are – pain in the bitten area, and sweating.

Male redback spiders’ venom is not dangerous to humans.


Facts About Redback Spiders

Did you know that spiders cannot chew their food, but instead suck their food? Once an edible prey is caught in the web, the redback spider attacks it by injecting its venom. The venom paralyzes the prey. Since the spiders cannot chew it, the redback injects strong digestive enzymes into its prey which turn it into a juicy/ soupy material that can be sucked.

Female redback spiders

Mostly every redback spider you see is a female redback spider. Male redback spiders are rare and die early. Female redback spiders are also much bigger in size.

The lifespan of a male redback spider is 6-7 months, while that of a female redback spider is about 2-3 years.

In winters, it is usually seen waiting patiently for the food to get trapped in the web. They can sometimes even wait for months during winters. The female redback spider can survive for 3 months without food.

The stripe on the body of a female redback spider is more orange/red. The stripe on the body of a male redback spider is redder, and also much less prominent.


The female redback spider’s body is of the size of a large pea, i.e., about 1 cm. The male redback spider length is 3 mm – 4 mm.

Reproduction and sexual cannibalism

The female redback spider releases pheromones on its web to indicate sexual availability. The males have to be cautious in approaching a female. If the female shows any aggressive signs, the male has to retreat, or it gets eaten.

The male redback spiders do not have a copulatory organ but collect its sperm in a sac which it puts into the sperm receptacles of the female. While the male is doing so, the female releases digestive enzymes. Numerous times, the male is unable to insert the sperm sac into the sperm receptacles and dies before it can do so. The female then sucks up the digested male redback spider.


Redback spiders feed on other smaller spiders, lizards, and insects. They can even steal prey from other redback spiders.

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