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Opiliones

life science Maturity 5-7 Next article →

You might know these creatures as daddy long legs or harvestmen. They are part of a group called Opiliones. People often mistake them for spiders, but they are actually a very different kind of arachnid.

Harvester body close up
Harvester body close up

While spiders have two separate body parts, harvestmen have a single oval body. This happens because their cephalothorax and abdomen are fused together. They also have only one pair of eyes in the middle of their head. Most spiders have three or four pairs of eyes around the edges of their head.

Harvestman macro
Harvestman macro

Harvestmen have a very interesting way of moving through the world. Because their eyes cannot form clear images, they rely on their legs. Their second pair of legs is much longer than the others. These long legs act like antennae, which are feelers used to explore.

Opiliones
Opiliones

They use these legs to sense what is around them. Most harvestmen are omnivores, meaning they eat many different things. They eat small insects, plants, and even fungi. Some are scavengers that eat dead things or bird dung.

Harvestman eating skink tail
Harvestman eating skink tail

Scientists have found that these animals have been around for a very long time. Fossils have been discovered in Scotland that are 400 million years old. There are also fossils found in France that are 305 million years old.

Rilaena triangularis 269725984
Rilaena triangularis 269725984

These ancient fossils look surprisingly modern. This shows that their basic body shape has changed very little over millions of years. It is amazing to think they have looked this way for so long. Scientists use these fossils to study how they are related to other arachnids.

There are over 6,650 known species of harvestmen living all over the world. Some scientists believe there might actually be more than 10,000 species.

Opiliones
Opiliones

They live on every continent except for Antarctica. In 2014, scientists named five different suborders to help group them. These groups are Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi. Some harvestmen are tiny, measuring less than 1 mm long. However, the largest species, Trogulus torosus, can grow as long as 1 cm.

Opiliones 20100626
Opiliones 20100626

Living together can be a smart way to stay safe. Many harvestmen are gregarious, which means they like to live in large groups. Some groups can have more than 70,000 individuals!

Opiliones 20100626
Opiliones 20100626

Staying in a crowd helps protect them from predators. If a predator attacks, the harvestmen can use scent glands to release a smelly fluid. This fluid can be quite unpleasant to animals that try to eat them. They also use camouflage to hide among leaves and dirt. This helps them blend into the ground so they are not seen.

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🖼️ Images & Media (12)
File:Pseudo-araña nocturna (opilion).jpg
Pseudo-araña nocturna (opilion).jpg
File:Harvester body close up.jpg
Harvester body close up.jpg
We-2012-09-09.ogv
File:Harvestman macro.jpg
Harvestman macro.jpg
File:Harvestman eating skink tail.jpg
Harvestman eating skink tail.jpg
File:Harvestman Opiliones grooming 2016-05-15.jpg
Harvestman Opiliones grooming 2016-05-15.jpg
File:Opiliones.jpg
Opiliones.jpg
File:Parasitismus.jpg
Parasitismus.jpg
File:Opiliones 20100626.jpg
Opiliones 20100626.jpg
File:Rilaena triangularis 269725984.jpg
Rilaena triangularis 269725984.jpg
File:Harvestman Mouth.JPG
Harvestman Mouth.JPG
File:Opiliones chelicerae photo.jpg
Opiliones chelicerae photo.jpg
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