Invertebrates

Invertebrates are the newest category of exotic pet to develop mature, widely-agreed husbandry standards, and one theme runs through nearly all of them: minimal handling is the current best-practice recommendation, not a workaround for a 'difficult' animal. Tarantulas in particular can be seriously injured or killed by a fall from even a modest height, and most keeper-facing guidance across this group has shifted toward observation-based care over the past decade rather than the handling-forward approach common with vertebrate pets.

Humidity and substrate depth are the two variables that most directly affect this group's wellbeing day to day. Terrestrial tarantulas need enough substrate depth and the correct humidity range to support a clean molt — one of the most vulnerable processes in this animal's life cycle — while hermit crabs specifically need access to appropriately-sized replacement shells and correct humidity to molt and grow safely without becoming shell-stressed.

Feeding in this group tends toward infrequent by vertebrate standards — many tarantulas and scorpions eat roughly weekly to biweekly as adults, and extended voluntary fasts of weeks or longer are frequently completely normal rather than a sign of a problem, particularly around a molt.

The species and problem pages linked from this hub cover specific enclosure setup, humidity, and feeding schedules per animal, and the disease pillars cover the molting, dehydration, and mite-related conditions that are the most common concerns across this group specifically.

Molting is the single most vulnerable process in the life of nearly every invertebrate covered here, and it deserves group-level understanding beyond any one species page: a tarantula, scorpion, or hermit crab mid-molt is temporarily soft-bodied and effectively defenseless, and correct humidity and an undisturbed environment during this window matter more than almost any other husbandry variable for this category. A molting invertebrate that looks motionless, oddly positioned, or 'dead' is very often simply mid-molt — checking the species page for what a normal molt posture looks like before assuming the worst prevents a lot of unnecessary panic and, more importantly, a lot of well-meaning but harmful interference.

Lifespan varies as dramatically in this group as in any other covered on ExoKeeper, and sex plays an unusually large role for some species: female tarantulas commonly live 15-25+ years depending on species, while males of the same species often live only 3-7 years, reaching maturity and then dying relatively soon after their final molt — a genuinely different ownership timeline depending on which sex is acquired, and one worth understanding before buying a juvenile whose sex isn't yet determinable.

Enclosure dimensions for this group follow a different logic than for vertebrate pets: for ground-dwelling species like most tarantulas and scorpions, height is often a hazard rather than a benefit, since a fall from even a modest height can rupture a tarantula's abdomen fatally, so floor space scaled to the animal (roughly 3x leg span for terrestrial tarantulas) with deliberately limited climbing height is the safer default, in contrast to the taller, climbing-oriented enclosures appropriate for arboreal reptile and amphibian species.

Because most invertebrates in this group don't display illness or distress the way a vertebrate does — no vocalization, limited facial expression, minimal visible body language beyond posture and general activity level — keepers benefit from learning what normal baseline behavior looks like for their specific animal early on (typical resting posture, typical activity pattern, typical time between meals) so that a genuine deviation is easier to recognize against that baseline rather than trying to interpret behavior from general first principles.

Defensive mechanisms vary considerably across this group and are worth understanding specifically rather than generically — tarantulas of certain species can flick urticating (irritant) hairs that cause skin and eye irritation, scorpions deliver a venomous sting whose severity varies enormously by species (most pet-trade species are mild, but not all), and hermit crabs simply withdraw into their shell. Handling minimally and researching the specific defensive profile of a given species before acquisition, rather than assuming 'invertebrate' implies uniformly low risk, is a reasonable baseline precaution.

Legal status is worth a brief mention for this category specifically, since it varies by jurisdiction more than for most other pets covered on this site — certain scorpion, tarantula, and other invertebrate species are restricted or require permits in some regions due to invasive-species or venom concerns, and checking local regulations before acquiring a less common invertebrate species is a practical step easy to overlook when a purchase can often be made online with no id or permit check at the point of sale.

Cost and equipment needs for this category are generally lower than for most reptiles, birds, or mammals covered on this site — no UVB bulb replacement schedule for most species, no large enclosure footprint, modest feeding costs — which is part of why invertebrates are sometimes recommended as a genuinely lower-maintenance entry point into exotic pet keeping, though 'lower-maintenance' shouldn't be read as 'no research needed,' since the consequences of a specific husbandry mistake (a fatal fall during a molt, incorrect humidity) can still be entirely irreversible.

Sexing many invertebrate species is genuinely difficult or impossible without specialized technique or waiting for a molt to reveal sex-specific features, which matters practically for tarantulas given how dramatically male and female lifespans diverge — a buyer hoping specifically for a long-lived female companion animal should understand that a juvenile's sex often can't be confirmed with confidence at the point of purchase for many commonly kept species.

Community knowledge and care-sheet quality vary more within this category than in more established pet groups, since invertebrate keeping as a mainstream hobby is comparatively newer — cross-checking care information against more than one reputable source (the British Tarantula Society and similar established organizations, rather than a single forum post or unsourced social media claim) is a worthwhile habit specifically for this category.

Temperament and 'personality' are more individually variable within a single species in this group than casual marketing sometimes suggests — a Chilean rose tarantula's reputation for being docile is a fair generalization, but individual animals of the same species genuinely range from consistently calm to considerably more defensive, and a new keeper should expect and plan for that individual variation rather than assuming a species reputation guarantees a specific animal's exact temperament.

Rehoming and secondhand acquisition are reasonably common in this category, since invertebrate keepers sometimes downsize a collection or age out of the hobby, and a secondhand tarantula or scorpion from an experienced keeper who can document feeding and molt history is often a lower-risk acquisition than an unlabeled juvenile of uncertain age at a general pet store — worth considering as a genuine option alongside buying new from a specialist breeder.

Shipping live invertebrates is common practice within this hobby and generally safe when done by an experienced seller using appropriate temperature-controlled packaging, but it's worth confirming a seller's shipping track record before ordering, since temperature extremes in transit are a genuine and largely preventable risk to a shipped animal's health on arrival.

Because this category includes some of the longest-lived pets covered on this entire site (a female tarantula potentially outliving a dog or cat by a wide margin) alongside some of the shortest-lived (certain male tarantulas, some feeder-adjacent species), checking the specific expected lifespan for the specific species and sex before acquiring it remains the single most important piece of research for this category, more than for almost any other group on ExoKeeper.

Feeder-insect husbandry deserves a brief mention on its own, since several invertebrate species on this site are themselves sometimes kept as display/breeding colonies as much as feeder stock (dubia roaches and isopods, for example) — gut-loading and correctly housing feeder colonies is a small sub-hobby within this category that meaningfully improves the nutritional quality of what ends up feeding a keeper's other exotic pets.

Observation as a hobby in its own right is a genuine appeal of this category that's easy to undersell relative to more interactive pets — watching a tarantula construct a burrow, a hermit crab explore and select a new shell, or an isopod colony process leaf litter offers a different, patient kind of engagement than a bird or mammal's more overt interactivity, and it's worth choosing this category deliberately for that reason rather than only as a lower-maintenance fallback option.

Multi-species bioactive enclosures — a tarantula or scorpion housed alongside a cleanup crew of isopods and springtails that break down waste and leftover feeders — are an increasingly popular setup style within this category, reducing cleaning frequency and adding a small ecosystem element on top of the primary animal's care, provided the cleanup crew species is genuinely compatible and non-threatening to the primary resident.