Stick insects are insects belonging to the order Phasmatodea (sometimes referred to as Phasmida). They are known under different names in different parts of the English speaking world. In Europe, they are simply called stick insects while people in the United States usually refer to them as walking sticks or stick bugs. Other names for these insects include phasmids, ghost insects and leaf insects. The scientific name Phasmatodea is derived from the greek word "phasma" meaning apparition or phantom; a reference to this creature’s uncanny ability to hide. It can be very hard to notice these insects when they are not moving.

Care is recommended whenever handling stick bugs as some stick insects can secret a substance that causes an intense burning sensation if you get it in your eyes or in your mouth. It can even cause temporary blindness.

Walking sticks moult when they grow larger as all insects do due to their hard exoskeleton and the growth restriction that would put on the insect if it didn’t shed its exoskeleton in favour of a new and larger one every now and again.

Some of the worlds largest insects are walking sticks. Females in the genus Phobaeticus can reach 33 cm / 13 in making them longest of all insects. There are also very heavy stick insects such as the female Heteropteryx dilatata that weighs up to 65 grams / 0.14 pounds. The heaviest insect in the world weighs 70 grams / 0.15 pounds.

The order Phasmatodea can be said to be in a state of disarray at the moment and revisions are common. How to divide the suborders have led to some controversy within the scientific community and so have the question of which species that belong to which families and genre. There are around 3,000 described species of stick insects and a lot of stick insects are waiting to be described so the number will rise as soon as someone gets around to it.

Walking sticks can be found in most habitats around the world but are most numerous in tropical areas near the equator. Some species like praying mantises are predatory while other stick insects are herbivores.

Stick insects are easy to care for in captivity and can make excellent pets as long as you’re not looking for a social animal suitable for cuddling. Over 300 species of walking stick have been kept and breed in captivity. The type of walking stick you usually see in pet stores is Carausius morosus, better know as Indian stick insect or sometimes Laboratory stick insect.  This species is very easy to keep and can be housed in room temperature in a 25 cm / 10 inch high jar with some holes in the lid. Add some lettuce, ivy, privet or other vegetables to give your insects something to eat. It should be noted that the Indian stick insect is one of the few stick insects that eat privet. All specimens of this species are females that reproduce by parthenogenesis (virgin birth) and it is therefore possible to get baby walking stick even if you keep only one Indian stick insect. They lay their eggs after the 6th moult. They do not need company. Other species of stick insects put bigger demands on their owner even though most species are easy to care fore.

Most species of walking stick will eat bramble and lettuce in captivity but some species have a specialized diet making them anything from hard or next to impossible to keep in captivity.

Stock insects lay eggs and a single insect can lay up to 500 eggs a year. If you breed stick insects in captivity you will need to spray the eggs to keep them moist. Young sticks easily drown if there are any pools of water in the vivarium so only spray lightly.