Vermont’s diverse ecosystems provide habitat for dozens of fascinating caterpillars in Vermont, from the iconic monarch to potentially dangerous species like the puss caterpillar. Whether you’re exploring the Green Mountains or your backyard garden, you’ll encounter these remarkable creatures transforming from larvae into beautiful butterflies and moths.
Understanding how to identify these caterpillars can enhance your nature experiences while keeping you safe from the few species that pose risks.
This comprehensive guide covers 31 caterpillars commonly found throughout Vermont, complete with identification tips and safety information.
You’ll discover everything from colorful swallowtail larvae to impressive sphinx moth caterpillars, helping you become a more knowledgeable observer of Vermont’s incredible insect diversity.
1. Monarch Caterpillar
The monarch caterpillar (Danaus plexippus) stands as Vermont’s most recognizable caterpillar with its distinctive black, white, and yellow striped pattern. You’ll find these striking larvae exclusively on milkweed plants throughout Vermont’s meadows, roadsides, and gardens from late spring through early fall.
These caterpillars grow to about 2 inches long and feature bold yellow, black, and white stripes running across their body segments. Two pairs of black tentacles extend from their head and rear, giving them an almost alien appearance. The bright coloration serves as a warning to predators that they’re toxic, having absorbed poisonous compounds from their milkweed host plants.
Pro Tip: Monarch caterpillars are completely safe to handle and make excellent subjects for nature photography and educational observation.
Look for monarchs on common milkweed, swamp milkweed, and butterfly weed plants. They’re most active during daylight hours and can often be spotted munching on milkweed leaves. Different types of caterpillars may share the same habitat, but monarchs are unmistakable once you know their pattern.
2. Black Swallowtail Caterpillar
The black swallowtail caterpillar (Papilio polyxenes) displays a stunning transformation as it matures, changing from a small black larva with white markings to a beautiful green caterpillar adorned with black bands and orange spots. You’ll commonly encounter these caterpillars in Vermont gardens, particularly on plants in the carrot family.
Young black swallowtail caterpillars resemble bird droppings, providing excellent camouflage protection. As they grow, they develop the characteristic green coloration with black bands containing orange or yellow spots. When threatened, they extend a bright orange forked organ called an osmeterium from behind their head, releasing a strong odor to deter predators.
These caterpillars feed primarily on parsley, dill, fennel, and wild carrot (Queen Anne’s lace). You might find them in herb gardens, wildflower meadows, or along roadsides where their host plants grow. Research shows that black swallowtails have expanded their range northward in recent decades, making them increasingly common in Vermont.
3. Eastern Tiger Swallowtail Caterpillar
The eastern tiger swallowtail caterpillar (Papilio glaucus) undergoes one of nature’s most dramatic transformations, starting as a brown and white “bird dropping” mimic before becoming a smooth green caterpillar with distinctive eyespots.
These large caterpillars can reach up to 2.5 inches in length and are found throughout Vermont’s deciduous forests.
Mature eastern tiger swallowtail caterpillars display a bright green body with two prominent false eyespots near the head, designed to startle potential predators.
A yellow and black band separates the head region from the body, creating an intimidating face-like appearance. Like other swallowtail caterpillars, they possess an osmeterium for chemical defense.
You’ll find these caterpillars feeding on cherry, birch, tulip tree, and ash trees throughout Vermont’s forests and suburban areas. They prefer the upper canopy but occasionally venture to lower branches where you can observe them. Similar species occur throughout the eastern United States, making identification skills valuable for any naturalist.
4. Giant Swallowtail Caterpillar
The giant swallowtail caterpillar (Papilio cresphontes) earns its common name “orangedog” due to its mottled brown and cream coloration that perfectly mimics bird droppings. This clever disguise makes it one of the most difficult caterpillars to spot in Vermont, despite being one of the largest butterfly larvae in North America.
These impressive caterpillars can grow up to 2.5 inches long and feature an irregular pattern of brown, tan, and cream patches across their body.
The coloration varies slightly between individuals, but all share the characteristic bird dropping appearance that provides excellent protection from predators. When disturbed, they extend their orange osmeterium and may curl into a defensive position.
Giant swallowtail caterpillars feed on plants in the citrus family, including prickly ash, hop tree, and occasionally cultivated citrus in protected locations. Forest Service data indicates these butterflies have been expanding their range northward, making sightings in southern Vermont increasingly common.
5. Spicebush Swallowtail Caterpillar
The spicebush swallowtail caterpillar (Papilio troilus) showcases nature’s artistry with its smooth green body adorned with blue and yellow eyespots that create a snake-like appearance.
This remarkable mimicry helps protect the caterpillar from birds and other predators in Vermont’s woodland environments.
Young spicebush swallowtail caterpillars start as brown bird dropping mimics before developing into stunning green larvae with prominent false eyespots.
The mature caterpillar’s head region features a yellow band, while the body displays subtle blue markings and two large eyespots that make it appear much larger and more threatening than it actually is.
These caterpillars primarily feed on spicebush and sassafras, both common understory plants in Vermont’s deciduous forests. You might also find them on tulip tree, sweet bay, and camphor tree where available.
They often rest on the upper surface of leaves, relying on their snake-like appearance for protection. Related species throughout the eastern states share similar host plant preferences and defensive strategies.
6. Pipevine Swallowtail Caterpillar
The pipevine swallowtail caterpillar (Battus philenor) appears less frequently in Vermont compared to other swallowtails, but its distinctive appearance makes it memorable when encountered.
These caterpillars display a dark purple-black body covered with rows of orange or red tubercles, creating a striking and somewhat intimidating appearance.
Pipevine swallowtail caterpillars grow to about 2 inches in length and feature a smooth, glossy body with prominent orange-red projections arranged in neat rows.
The tubercles serve both as warning coloration and physical deterrents to predators. Like other swallowtail species, they possess an osmeterium for chemical defense.
These caterpillars feed exclusively on pipevine species, which limits their distribution in Vermont to areas where these host plants occur naturally or in cultivation.
Virginia snakeroot and wild ginger may also serve as host plants in some regions. Citizen science observations suggest pipevine swallowtails are gradually expanding their range northward with climate change.
7. Viceroy Caterpillar
The viceroy caterpillar (Limenitis archippus) demonstrates excellent camouflage with its mottled brown and white coloration that resembles a bird dropping when at rest. These caterpillars are commonly found throughout Vermont on willow and poplar trees, where they create distinctive leaf shelters for protection.
Viceroy caterpillars reach about 1.5 inches in length and display an irregular pattern of brown, tan, and white markings. Two prominent projections extend from behind the head, giving them a distinctive silhouette. The caterpillar’s body appears somewhat flattened, helping it press close to branches and leaves for better concealment.
Key Insight: Viceroy caterpillars create winter shelters by rolling leaves and securing them with silk, making them one of the few butterfly species that overwinter as larvae in Vermont.
Look for these caterpillars on willows, poplars, and cottonwoods throughout Vermont’s wetland areas and stream corridors. They often rest along leaf midribs where their coloration provides excellent camouflage. Various caterpillar species use similar camouflage strategies, but viceroys are unique in their leaf-rolling behavior.
8. Red Admiral Caterpillar
The red admiral caterpillar (Vanessa atalanta) creates distinctive silk shelters on nettle leaves, making them relatively easy to locate despite their secretive nature. These spiny caterpillars vary in color from pale green to dark brown or black, often with lighter striping along their sides.
Red admiral caterpillars grow to about 1.5 inches long and feature numerous branched spines covering their body. The spines appear intimidating but are actually quite soft and harmless to handle. Coloration ranges widely, with some individuals appearing almost black while others display bright green or brown hues with contrasting stripes.
These caterpillars feed almost exclusively on nettles, including stinging nettle and false nettle. You’ll find them throughout Vermont in areas where nettles grow, including forest edges, disturbed soils, and garden margins.
They create silk shelters by folding nettle leaves and feeding from within these protective structures. Migration studies show red admirals cannot survive Vermont winters, requiring annual recolonization from southern populations.
9. Painted Lady Caterpillar
The painted lady caterpillar (Vanessa cardui) displays remarkable adaptability in its host plant selection, feeding on over 100 different plant species throughout Vermont. These spiny caterpillars create silk shelters similar to red admirals but show much greater flexibility in their habitat preferences.
Painted lady caterpillars reach about 1.5 inches in length and feature a body covered with branched spines and variable coloration ranging from pale yellow-green to dark brown or black. Light and dark stripes often run along the body, and the head capsule typically appears darker than the body segments.
You might encounter painted lady caterpillars on thistles, mallows, sunflowers, legumes, and many other plant families throughout Vermont. Their broad diet allows them to colonize diverse habitats from gardens to wild meadows.
Like red admirals, they create protective silk shelters on their host plants. These widespread species occur across North America, demonstrating remarkable ecological adaptability.
10. American Lady Caterpillar
The American lady caterpillar (Vanessa virginiensis) closely resembles the painted lady but shows a stronger preference for plants in the aster family.
These spiny caterpillars create communal silk nests when young, later becoming solitary as they mature and develop their characteristic protective shelters.
American lady caterpillars grow to about 1.25 inches long and display variable coloration from pale green to dark brown or black, often with distinctive white, yellow, or pale green stripes.
The branched spines covering their body appear more prominent than those of painted ladies, and the overall body shape tends to be slightly more robust.
These caterpillars primarily feed on everlasting, cudweed, burdock, and other plants in the aster family. You’ll find them in Vermont’s fields, meadows, and disturbed areas where their preferred host plants grow.
Young caterpillars often feed together in silk webs before dispersing to create individual shelters. Tracking data shows American ladies have multiple generations per year in Vermont, with peak abundance in late summer.
11. Mourning Cloak Caterpillar
The mourning cloak caterpillar (Nymphalis antiopa) creates one of nature’s most impressive communal feeding displays, with dozens of spiny black caterpillars clustering together on willow and elm branches.
These gregarious larvae remain together through most of their development, creating conspicuous feeding aggregations throughout Vermont.
Mourning cloak caterpillars reach up to 2 inches in length and display a striking black body covered with white spots and red-orange markings.
Rows of branched black spines extend from each body segment, giving them a fearsome appearance that effectively deters many predators. The spines are harmless to humans but provide excellent protection from birds.
You’ll find these caterpillars feeding communally on willows, elms, poplars, and birches throughout Vermont. Large groups can defoliate entire branches, making them easy to spot during peak feeding periods.
The caterpillars remain together until just before pupation, when they disperse to find suitable pupation sites. Northern populations of mourning cloaks produce some of the longest-lived butterflies in North America.
12. Milbert’s Tortoiseshell Caterpillar
Milbert’s tortoiseshell caterpillar (Aglais milberti) forms dense colonies on nettle plants, creating impressive feeding aggregations that can include hundreds of individuals. These spiny caterpillars display variable coloration but maintain their gregarious behavior throughout most of their larval development.
These caterpillars grow to about 1.25 inches long and feature bodies covered with branched spines and variable coloration ranging from pale green to dark brown or black. Many individuals display distinctive yellow or orange markings, particularly along the sides of their body segments. The spines appear formidable but are completely harmless to handle.
Important Note: Milbert’s tortoiseshell caterpillars create some of the largest communal feeding groups of any butterfly species in Vermont, sometimes numbering in the hundreds on a single nettle patch.
Look for these caterpillars on stinging nettles throughout Vermont, particularly in moist areas near streams, forest edges, and disturbed soils. The communal feeding groups can quickly defoliate nettle patches, making them highly visible during peak feeding periods. Distribution studies show this species thrives in cooler climates, making Vermont ideal habitat for stable populations.
13. Cecropia Moth Caterpillar
The cecropia moth caterpillar (Hyalophora cecropia) ranks as one of Vermont’s most impressive caterpillars, growing up to 4.5 inches long with a spectacular array of colorful tubercles and spines. This giant silk moth caterpillar transforms from a small black larva into a magnificent blue-green creature adorned with red, orange, and yellow projections.
Mature cecropia caterpillars display a blue-green body with rows of colorful tubercles running along their back and sides. The tubercles range from bright red and orange to yellow and blue, creating one of nature’s most striking caterpillar displays. Despite their intimidating appearance, these caterpillars are completely harmless and fascinating to observe.
These caterpillars feed on a wide variety of trees including maple, birch, cherry, apple, and many others throughout Vermont. You might find them in forests, orchards, or suburban areas where their host trees grow. Large moth caterpillars like cecropias play important ecological roles as both herbivores and prey species for various predators.
14. Polyphemus Moth Caterpillar
The polyphemus moth caterpillar (Antheraea polyphemus) appears as a bright green giant with distinctive red and silver spots arranged along its body segments. These impressive caterpillars can reach 3.5 inches in length and rank among Vermont’s most commonly encountered large moth larvae.
Polyphemus caterpillars feature a bright lime-green body with diagonal white stripes on each segment and prominent red or orange spots with metallic silver centers. The caterpillar’s segments appear distinctly separated, giving it a segmented appearance that’s quite different from most other large moth caterpillars. Small bristles cover the body, but these are harmless to touch.
You’ll find polyphemus caterpillars on oak, maple, birch, willow, and many other deciduous trees throughout Vermont. They’re often discovered by accident when pruning trees or during late-season garden cleanup. Observation records show these caterpillars are most commonly found in late summer and early fall when they reach their maximum size.
15. Luna Moth Caterpillar
The luna moth caterpillar (Actias luna) presents a stunning lime-green appearance with distinctive red spots and a subtle blue tint that makes it one of Vermont’s most beautiful caterpillars. These impressive larvae grow up to 3.5 inches long and feed on a variety of deciduous trees throughout the state.
Luna moth caterpillars display a bright green body with a subtle bluish tint and prominent red spots arranged along their back. Yellow stripes run along the sides, and the entire body appears smooth and almost translucent. The caterpillar’s color provides excellent camouflage among green leaves, making them challenging to spot despite their large size.
These caterpillars feed on walnut, hickory, birch, alder, and other deciduous trees in Vermont’s forests and suburban areas. They’re most active at night and often rest motionless on leaves during daylight hours. Eastern populations of luna moths face increasing challenges from light pollution and habitat fragmentation, making conservation efforts important.
16. Promethea Moth Caterpillar
The promethea moth caterpillar (Callosamia promethea) displays remarkable sexual dimorphism, with males and females showing distinctly different coloration patterns. These medium-sized caterpillars reach about 2.5 inches in length and create distinctive cocoons that remain attached to their host trees through winter.
Promethea caterpillars vary significantly in appearance between sexes and individuals. Some display bright green coloration with red, yellow, and black tubercles, while others appear more bluish-green or even pale yellow. All feature prominent tubercles arranged in rows along their body segments, creating a distinctive spiky appearance that’s harmless to touch.
You’ll find these caterpillars on cherry, ash, tulip tree, sweetgum, and spicebush throughout Vermont. They prefer forest edges and openings where their host plants receive good sunlight. Research indicates promethea moths show strong site fidelity, often returning to the same areas year after year.
17. Io Moth Caterpillar
The io moth caterpillar (Automeris io) demands respect as one of Vermont’s few caterpillars capable of delivering a painful sting. These distinctive green caterpillars feature rows of branched spines that contain venomous compounds, making proper identification crucial for safe outdoor exploration.
Io moth caterpillars display a bright green body covered with clusters of branched spines that appear white or pale green. Red and white stripes run along the sides of their body, and the overall appearance is quite striking. The spines contain irritating compounds that can cause significant pain and welts if contacted, similar to stinging nettle but more intense.
Important Note: Never handle io moth caterpillars directly. Their venomous spines can cause painful stings lasting several hours. Use tools or protective gear if removal is necessary.
These caterpillars feed on a wide variety of plants including corn, roses, willow, cherry, and many others throughout Vermont. You might encounter them in gardens, fields, or forest edges. Stinging caterpillars occur throughout North America, making identification skills essential for outdoor enthusiasts.
18. Imperial Moth Caterpillar
The imperial moth caterpillar (Eacles imperialis) showcases remarkable color variation, ranging from green to brown to nearly black, often with distinctive spines and markings that change as the caterpillar matures. These large caterpillars can reach up to 4 inches in length and represent one of Vermont’s most variable species.
Imperial moth caterpillars display incredible diversity in coloration and pattern. Some individuals appear bright green with yellow stripes, while others show brown, orange, or even dark burgundy coloration. Most feature prominent spines behind the head and scattered bristles across the body. The spines appear intimidating but are harmless to touch.
You’ll find imperial moth caterpillars on pine, oak, maple, sweetgum, and many other trees throughout Vermont. Their variable appearance can make identification challenging, but the distinctive spiny projections behind the head help distinguish them from other large caterpillars. Distribution data suggests imperial moths are becoming less common in northern parts of their range, making Vermont sightings particularly noteworthy.
19. Blinded Sphinx Caterpillar
The blinded sphinx caterpillar (Paonias excaecatus) features the characteristic horn typical of sphinx moth caterpillars, along with distinctive diagonal stripes that provide excellent camouflage among leaves and twigs. These medium-sized caterpillars grow to about 3 inches long and display remarkable color variation.
Blinded sphinx caterpillars show variable coloration from bright green to brown or pink, always featuring diagonal white or pale stripes running from the spiracles toward the back. A prominent horn extends from the rear segment, and the head often appears smaller in proportion to the robust body. The diagonal striping pattern helps break up their outline among foliage.
These caterpillars feed on cherry, willow, poplar, and birch throughout Vermont’s forests and suburban areas. They’re often found on young trees or saplings where their camouflage is most effective. Sphinx moth caterpillars are known for their rapid growth and impressive size, making them fascinating subjects for nature observation.
20. Small-eyed Sphinx Caterpillar
The small-eyed sphinx caterpillar (Paonias myops) closely resembles the blinded sphinx but typically shows more subdued coloration and slightly different striping patterns. These caterpillars demonstrate the subtle variations that make sphinx moth identification both challenging and rewarding for naturalists.
Small-eyed sphinx caterpillars display similar diagonal striping to blinded sphinx caterpillars but often appear more muted in coloration, ranging from pale green to brown or gray. The diagonal stripes may appear less distinct, and the overall body color tends toward more neutral tones. The characteristic sphinx moth horn remains prominent at the rear.
You’ll find these caterpillars on the same host plants as blinded sphinx caterpillars, including cherry, willow, and poplar trees throughout Vermont. The two species often occur in the same habitats, making careful observation necessary for accurate identification. Comparative studies show these closely related species may hybridize occasionally, further complicating field identification.
21. White-lined Sphinx Caterpillar
The white-lined sphinx caterpillar (Hyles lineata) displays one of the most variable color patterns among Vermont caterpillars, ranging from bright green with distinct markings to nearly black forms with contrasting stripes. These adaptable caterpillars feed on an unusually wide variety of host plants.
White-lined sphinx caterpillars show remarkable color variation but typically feature a prominent horn and distinctive markings that may include bright spots, stripes, or eyespots. Green forms often display yellow or white stripes, while darker forms may show contrasting light markings. All forms maintain the characteristic robust sphinx moth body shape.
These caterpillars feed on over 100 different plant species, including evening primrose, grape, elm, and many garden plants throughout Vermont. Their broad diet allows them to colonize diverse habitats from wild areas to cultivated landscapes. Migration tracking shows white-lined sphinx moths undertake impressive long-distance movements, contributing to their widespread distribution.
22. Hummingbird Clearwing Caterpillar
The hummingbird clearwing caterpillar (Hemaris thysbe) appears as a pale green larva with a distinctive horn and subtle markings that provide excellent camouflage on its host plants. These day-flying sphinx moth caterpillars create adults that perfectly mimic hummingbirds in flight.
Hummingbird clearwing caterpillars display a pale green body with a prominent horn and often feature subtle yellow or white markings along the sides. The body appears smooth and robust, typical of sphinx moth caterpillars, and the green coloration provides excellent camouflage among the leaves of their host plants.
These caterpillars feed primarily on honeysuckle, snowberry, and related plants throughout Vermont. You might find them in gardens, forest edges, or areas where ornamental honeysuckles are planted. Clearwing moths represent a fascinating group that demonstrates convergent evolution with hummingbirds, making them popular among naturalists and photographers.
23. Snowberry Clearwing Caterpillar
The snowberry clearwing caterpillar (Hemaris diffinis) closely resembles the hummingbird clearwing but shows subtle differences in coloration and host plant preferences. These pale green caterpillars create adults that also mimic hummingbirds, though with slightly different flight patterns and timing.
Snowberry clearwing caterpillars feature a pale green body with a prominent horn and may display more pronounced yellow or white markings compared to hummingbird clearwings.
The differences can be subtle, making host plant identification often more reliable than caterpillar appearance for distinguishing between these closely related species.
You’ll find these caterpillars on snowberry, dogbane, and honeysuckle throughout Vermont. They prefer more open habitats than hummingbird clearwings and may be found in meadows, prairies, and garden edges.
Behavioral studies show clearwing moths have adapted their flight patterns to closely match those of hummingbirds, providing protection from predators through Batesian mimicry.
