What Do Tarantulas Eat? Unveiling the Secrets of Their Dietary Habits

Tarantulas, those formidable yet often misunderstood arachnids, possess feeding behaviors as complex as their leg span and venom. Understanding what tarantulas eat reveals not just their survival strategies but also their ecological role as key predators in ecosystems worldwide. This article explores their feeding biology, revealing a diet shaped by species, environment, and evolutionary adaptation—equipped with fascinating details that go beyond the typical misconceptions.

Tarantulas are primarily carnivorous, relying exclusively on animal-based food sources. Unlike herbivorous insects, they do not consume plants or organic matter decaying on the forest floor. Instead, their diet centers on a diverse array of living prey, reflecting their position as skilled hunters in nocturnal food webs.

This article examines the types of prey tarantulas target, how feeding frequency correlates with size and age, their hunting and digestion methods, and how captivity alters feeding norms—offering a comprehensive view grounded in scientific observation.

Key Prey Species: From Insects to Small Vertebrates

The variety of prey consumed by tarantulas spans multiple insect classes and occasionally extends to small vertebrates, depending on species and habitat. While most tarantulas thrive on invertebrates, exceptional cases document predation on creatures far larger than their fangs suggest.

Insect Prey: The Foundation of Tarantula Diets Insects form the cornerstone of the tarantula diet across nearly all species. Common victims include moths, beetles, crickets, grasshoppers, and spiders—both diurnal and nocturnal. Their abundance and ease of capture make insects ideal nutritional sources.

For instance, the common Carolina tarantula (Astellina hentzi), native to Florida, frequently hunts day-active moths flying near its burrow entrance. Similarly, the Brazilian salmon pink birdeater (Lasiodora porta) subdues large beetles and cockroaches, leveraging its powerful fangs to deliver neurotoxic venom swiftly. Spider Predation: Surprising Tactics and Prey Size Though rare, some tarantula species target fellow arachnids.

The lesser greenbelt tarantula (Grammostola rosea), prized in captivity, has been observed preying on smaller spiders, particularly during mating seasons when rival males become vulnerable targets. This behavior underscores the adaptability of tarantulas: when larger or More competitive prey approaches its territory, feasting on smaller spiders may be a strategic survival response. Occasional Vertebrate Encounters While exceptional, tarantulas have been documented consuming small vertebrates, primarily amphibians and reptiles.

Juvenile mice, baby lizards, and small frogs occasionally fall prey, especially when ambushed near water sources or nesting sites. These incidents are not indicative of typical feeding but reflect opportunistic predation in resource-scarce environments. Notably, the Utila spitting cobalt blue tarantula (Pterinus lima) from Honduras may strike with speed sufficient to incapacitate small reptiles, though such events remain anecdotal and uncommon.

Diet Variation by Species: How Size Dictates Meal Preferences

Tarantula diet is not uniform across species; it scales with body size and metabolic demands. Larger tarantulas, capable of subduing bigger prey, often consume insects the size of small birds or rodents in the wild, a contrast to their smaller kin who rely solely on insects. Juveniles vs.

Adults: Developmental Shifts in Diet Young tarantulas, known as spiderlings, begin with micro-prey such as fruit flies, brine shrimp, and pinhead crickets—moving to larger insects over their first few molts. As they grow, molting frequency decreases, but their overall intake increases. During molting, tarantulas remain inactive and avoid feeding entirely, conserving energy for this vulnerable process.

Species-Specific Predilections Different tarantula families exhibit clear dietary biases. The Mygoseniidae, including the popular birdeater (Theraphosidae), favor large, nutrient-dense prey like cicadas and grasshoppers, aligning with their size and ambush hunting style. In contrast, the Pompilidae-associated tarantulas—though technically not true Theraphosidae—tend toward faster, more agile prey, reflecting their ecological niche as active hunters rather than sit-and-wait ambushers.

Feeding Frequency: From Daily Hunters to Weeks Between Meals

Tarantulas are not consistent feeders; their intake varies dramatically based on size, age, and environmental conditions. This irregular eating pattern reflects their metabolic efficiency and evolutionary adaptation to variable food availability. Growth-Related Feeding Patterns Juvenile tarantulas, undergoing rapid growth, may consume prey every few days.

A young tarantula might eat once weekly during its first year, then progress to every 2–3 days by its second year. Size increases from a few centimeters to over 10 centimeters in leg span over several molts, directly driving higher caloric needs. Environmental and Seasonal Influences In tropical zones with consistent warm climates, tarantulas often feed every 4–7 days year-round, capitalizing on high insect diversity.

In temperate regions, feeding slows significantly: some species go months between meals during colder months, when temperatures suppress insect activity. Captive tarantulas, shielded from seasonal extremes and given steady diets, may eat 3–6 times per month—though this depends on species, age, and enclosure conditions. Overfeeding poses greater risks than fasting, emphasizing precision in captivity.

Hunting Strategies and the Mechanics of Feeding

Tarantulas lack the visual acuity of many predators, relying instead on sensitive vibrations and chemical cues to locate prey. Their ambush strategy minimizes energy expenditure, a crucial adaptation for ectothermic hunters with limited metabolic reserves. Ambush Tactics Over Active Pursuit Most tarantulas remain motionless in silk-lined burrows or hiding crevices, relying on vibration-sensitive hairs on their legs and chaetobothrial organs to detect prey movement.

This sit-and-wait approach conserves energy and reduces risk. The owl spider (Aphonopelma hentzi), for example, waits motionless for nocturnal insects to trigger its sensitive leg receptors, ensuring a precise strike with minimal effort. Venom’s Dual Role: Subduing Prey and Preparation for Digestion Striking with venom is both a hunting and digestive tool.

Tarantulas inject neurotoxic compounds via chelicerae, immediately immobilizing prey—often within seconds. The venom not only paralyzes but begins breaking down tissue, liquefying internal organs for absorption. This rapid immobilization reduces escape risk and maximizes nutrient uptake, making feeding efficient even with infrequent meals.

Feeding in Captivity: Mimicking Nature in the Care of Pet Tarantulas

Replicating natural feeding habits in captivity is essential for the health and longevity of pet tarantulas, as improper diets directly impact lifespan and well-being. Prey Selection and Nutritional Balance Pet owners must prioritize feeder insects rich in protein and low in fat—staples like crickets, roaches, waxworms (sparingly due to high fat), and mealworms. Larger tarantulas may occasionally receive live mice, though this should be reserved for species capable of handling vertebrate prey, and introduced with caution to avoid injury.

Rep trophic cycling—offering prey about once every 7–14 days depending on molting cycle—aligns with species-specific needs and prevents overeating. Supplementing for Optimal Health While whole prey forms the base diet, calcium supplementation is critical, particularly during molting. Dusting insects with calcium powder or offering calcium-rich foods like mineral blocks supports exoskeleton hardening and overall physiological function.

Over time, consistent feeding habits contribute to stronger lives, deeper coloration, and longer, more vigorous molts—hallmarks of well-cared-for tarantulas. Tarantulas maintain a highly adaptive carnivorous diet centered on insects, occasionally expanded by small spiders or vertebrate prey, shaped by species, size, and environment. Their feeding behavior—rooted in ambush, precision, and conservation—reflects millions of years of evolutionary refinement.

Captive care, by mimicking natural patterns, enhances health and longevity. Understanding what tarantulas eat not only demystifies these arachnids but also underscores their vital role in ecological balance, ensuring we appreciate these creatures far beyond legend.