Long the domain of reptiles and amphibians, terrariums are increasingly becoming popular for homing captive invertebrates. Inherently small and well-suited to small aquariums, many invertebrates -- think tarantulas, millipedes and centipedes -- will thrive in the hands of dedicated keepers. Many invertebrates are protected by venom or poison, so exercise caution when selecting a pet.
Millipedes are among the few invertebrates you can keep in multi-creature colonies. They will cohabit with roaches and pill bugs quite well. Most millipede species consume dead and decaying plant material but will subsist on a diet of fruits and vegetables. Millipede habitats must reflect the natural habitat of the species; it is important to identify your millipede species correctly and research its natural habitat. Millipedes do not bite but may exude a foul smelling liquid that can stain the hands. In some species, this liquid may be poisonous -- harmful if touched or absorbed by a mucous membrane -- so parental supervision is mandatory for young invertebrate keepers.
Centipedes are venomous creatures who aren’t appropriate for young animal lovers but are interesting pets for knowledgeable, responsible people who are comfortable keeping them. Thousands of centipede species exist around the world; some tropical species exceed 12 inches in length and are as big around as a man’s thumb. These predators are often very speedy, hard to transfer from container to container. Centipedes hide most of the day. They consume crickets and roaches; large species will consume mice.
Among the tarantula species available to hobbyists, personalities and care requirements differ. The key is selecting the species best suited to you. Easily kept and docile species include Mexican red-knee (Brachypelma smithi), pink toe (Avicularia avicularia) and Chillean rose hair (Grammostola rosae) tarantulas. Other species, some beautiful, are better left to experienced keepers, including the highly aggressive king baboon tarantulas (Pelinobius muticus) and large Goliath bird-eating tarantulas (Theraphosa blondi). Some tarantulas require rainforest terrariums, while others prefer desert terrariums.
Scorpions, particularly emperor scorpions (Pandinus imperator), are kept as terrarium pets. While some species have very dangerous stings and should not be kept as pets, the popular emperor scorpions are not known to sting unless highly provoked. In general, the larger the claws of a scorpion, the weaker the venom; emperor scorpions have some of the largest claws known and have weak venom. Scorpion care is largely the same as terrestrial tarantula care; their diet is the same insect prey.
Praying Mantises and Walking Sticks
Praying mantises and walking sticks make interesting captive invertebrates. Praying mantises and other mantids are ambush hunters of insects that they capture on plants and flowers. Some species are ornately colored or beautifully camouflaged and make stunning display animals. Walking sticks aren’t kept as frequently, but they make interesting, if unexciting, subjects. They subsist on a vegetarian diet.
Hermit crabs are terrestrial invertebrates who require somewhat elaborate habitats -- they need climbing opportunities, fresh water and hiding and burrowing spaces. Additionally, hermit crabs require increasingly larger shells, they will swap out a smaller ones for larger ones as they grow. It is important to note that, despite their name, hermit crabs are gregarious: they should not be kept individually; keep hermit crabs in groups of five or so animals.
Thousands of invertebrate species can be kept in a terrarium; the primary criteria are that those you choose are sedentary enough to house properly and that you are comfortable with any potential danger they present. Hobbyists regularly keep tropical roaches, pill bugs, mealworms, silkworms, lady bugs and walking sticks as pets. It is important to note that many times, hobbyists keep the larval stage of an animal as a pet, and then release the adult into the wild; under no circumstances should keepers do this with non-native invertebrates.