Spiky caterpillars are an uncommon breed of moth or butterfly larvae.
These dark-colored insects, which resemble worms and can have jet-like bodies, light or white patterns, and fleshy spines or spikes on their bodies, can be intimidating.
Even though they have spikes on their bodies, most spiky caterpillars are not poisonous because they do not have poison-filled spines.
The great leopard moth caterpillar is the most frequent species with a spiny and spiky appearance.
These Spiky caterpillars’ surface has tufts of rigid and silky spines.
Other frequent types of caterpillars with spiny protrusions are peacock, spiny elm, and red admiral caterpillars.
Green caterpillars are the most common, although there are many other kinds.
On the other hand, there are also species of caterpillars with fuzzy appearances and yellow and brown caterpillars.
There are thousands of different species of caterpillars, but the group with spikes is the smallest.
You’ll find a total of 22 different species of spiny caterpillars on this list.
Are Spiky Caterpillars Poisonous?
Most caterpillars with spines or spikes are not dangerous to humans and do not have any venom-filled ends on their appendages.
Conversely, certain hairy caterpillars might have fine hairs called setae, known to irritate human skin.
Some species of spiky caterpillars, such as the mourning cloak and peacock caterpillars, have barbed spines. Because of this, picking them up may cause a stinging or burning feeling on your skin.
Even though they won’t hurt you if you touch them, it’s better to stay away from caterpillars with spikes, even though they don’t bite or sting.
How to Identify Spiky Caterpillars
To identify spiky caterpillars, one must examine their size, the sort of spines they have, the presence of hairs, and any distinctive markings they may have.
For instance, certain spiny caterpillars can resemble woolly bears, while others resemble spiny slugs.
The environment in which they live and the kinds of plants they consume can also help identify caterpillars.
Types of Spiky Caterpillars
1. Giant Woolly Bear
The big woolly bear caterpillar (Hypercompe scribonia) is a spiky caterpillar with red stripes running through its segments.
The big woolly bear caterpillar is a spiny insect with spines that are sharp and needle-like in appearance. It is also known as the giant leopard moth caterpillar.
When curled up, these Spiky caterpillars reveal distinct red stripes hidden beneath their spiny covering.
These bands are visible only when the caterpillar is in its contracted state.
The length of the spiny caterpillar is three inches or 75 millimeters.
The big woolly bear will curl into a ball to protect itself when it senses danger. This behavior is easily recognizable.
This action causes these Spiky caterpillars to expose orange-red bands around their bodies.
Because of this movement, the caterpillar is easy to detect due to the bright red stripes wrapped around its body.
The spines of the leopard moth caterpillar do not contain poison. Nevertheless, although the caterpillar appears fluffy, the spikes are very pointed.
After removal, these irritating hairs can create a burning feeling and a red rash.
Therefore, even though a gigantic woolly bear isn’t dangerous, it’s better to avoid coming into contact with this spiny beetle.
The huge woolly bear caterpillar does not begin its life as an insect that resembles a spiny worm.
Instead, the small caterpillar is orange and has scattered tufts of setae (irritating hairs) on its body throughout the first few stages of its life.
It transforms into a caterpillar covered in glossy, bristly setae when it reaches maturity.
After emerging from its stage as a pupa, the Great Leopard Moth is the adult form of the Giant Woolly Bear.
This magnificent white moth has markings on its wings, and its body is iridescent blueish-gray with orange markings.
The caterpillars of the Spiked Woolly Bear are known to feed on a wide variety of woody plants, ornamental shrubs, and crops.
The cabbages, citrus trees, willows, dandelions, sunflowers, and violets are only a few of the plants that host fuzzy creatures.
Other insects, birds, and animals that eat big woolly bear caterpillars may get sick from eating them.
Researchers believe that the chemicals they consume from the plants they eat create a material in their bodies that is disagreeable to taste.
Additionally, their rigid spines serve as a natural defense strategy for the animal.
The body of the huge woolly bear caterpillar is marked all over with bright red stripes and coated in spiky spikes.
The bright crimson stripes develop between the dense tufts of spikes on the caterpillar only when it rolls up to defend itself.
2. Peacock Caterpillar
The peacock caterpillar (Aglais io) is a shiny worm-like caterpillar with white spots and barbed spikes covering its slender body.
Its name comes from the peacock butterfly, which the peacock caterpillar resembles. The larva is easy to recognize because it has six rows of spurs.
This peculiar insect is around 1.5 inches (40 mm) long and has a scary aspect of going along with its size.
This creeping insect has a soft body and a jagged appearance, including a rounded head. The spiky caterpillar is not poisonous, although it appears quite dangerous.
Its spines are glossy and velvety, and its barbs are very fine. However, it doesn’t sting or bite people and is safe to handle.
Stinging nettles are the sole source of nutrition for peacock caterpillars (Urtica). Spiked caterpillars tend to congregate in large numbers and live communally in silken nests spun communally over the host plant.
Once it has metamorphosed, the peacock caterpillar emerges as a beautiful orange-brown butterfly.
The magnificent winged creature is identifiable by the enormous eyespots that are on both of its wings.
The peacock caterpillar has a shiny body covered in white spots, rows of barbed spines, and a spherical head.
In addition, these Spiky caterpillars have four pairs of tan-hued prolegs (false legs).
3. Spiny Elm Caterpillar
The body of the spiky elm caterpillar (Nymphalis antiopa) is covered with orange-red patterns and numerous tiny white spots.
These Spiky caterpillars, also known as the mourning cloak caterpillar, have a slender body covered in spikes and white dots.
In addition to that, there is a line of reddish-orange dots that run up its back. The length of the caterpillar is 1.5 inches or 38 millimeters.
The peacock caterpillar and the spiny elm caterpillar are very similar, except for a dramatic line of red spots on the peacock caterpillar’s back.
The caterpillar’s body has minute white speckles and a band of spines wrapped around each segment of its body.
The caterpillar of the prickly elm tree is not a poisonous species and will not harm humans.
It is possible to assume that the caterpillar is a stinging kind since it has rows of spines that look jagged.
However, this is not the case because the spines that are so dazzling are on the softer side.
The caterpillars of the spiny elm are known by their common name because they feed on the foliage of elm trees.
Nevertheless, the insects can also damage the foliage of poplar, willow, and birch trees.
Following the pupation process, these Spiky caterpillars transform into huge brown butterflies with an eye-catching yellow margin along the edges of their wings.
A line of iridescent blue dots is visible at the edge of its wings. The butterfly, which is easy to identify due to its distinctive markings, also has the longest lifespan of any insect that belongs to the order Lepidoptera.
The body of the spiny elm caterpillar has recognizable reddish patches, white speckles, and mushy barbed spines.
4. Red Admiral Caterpillar
The body of the red admiral caterpillar (Vanessa atalanta) is spiky, and it has tiny white dots and creamy-yellow spots around its legs.
The red admiral caterpillar is a spiky, slender caterpillar with a body covered in small white spots. Its name comes from the butterfly it transforms into.
This caterpillar is identifiable by its rows of fleshy spines, which give it a spiky appearance and serve as its distinguishing trait. Red admiral caterpillars can reach 1.4 inches (35 mm).
Individual red admiral caterpillars may have somewhat different coloring. Some types have a light brown coloration and dots all over their sides with a yellowish-cream color.
On the other hand, some have a shiny appearance with spikes and a white stripe that runs down their abdomens. Most caterpillars have a head coated in spines and hairs of varying lengths.
These Spiky caterpillars develop through several phases similar to those of other caterpillars (instars). Immature caterpillars have white speckles and spines on their bodies and are long and slender.
The caterpillar has reached its final instar and has transformed into a dark brown color with a round and full appearance.
The stinging nettle and the fake nettle are the preferred foods of the innocuous red admiral caterpillar.
The formerly spiny caterpillar transforms into a stunning brown butterfly once it has metamorphosed within the chrysalis.
The wings of the medium-sized butterfly are either black or dark brown, with white dots and vivid red stripes.
The red admiral caterpillar is a crawling insect with a slender, spiked body. It is very easy to recognize.
A row of dark spines runs transversely down each segment of the caterpillar, and there is a creamy white dot near each segment’s legs.
5. Sweet Gale Moth Caterpillar
The larva’s body of the sweet gale moth (Acronicta euphorbiae) has some orange and white lines, with bristles covering every part of its body.
The larva of the sweet gale moth looks like a dark gray caterpillar with hairy spikes covering its body.
The early stages of these Spiky caterpillars are characterized by a slender body, an orange band running along the abdomen, and a grayish-white stripe running along the back.
The little caterpillar has tufts that resemble thin spines all over its body. When fully grown, the larva of the sweet gale moth measures approximately 1.3 inches (33 millimeters) in length.
Following metamorphosis in the pupal stage, the once spiny caterpillar has transformed into a multicolored fuzzy caterpillar.
The caterpillar has orange, dark gray, white coloring, and yellow tips. The caterpillar maintains its head through each instar.
During the latter part of spring and the beginning of summer, You may find caterpillars of the sweet gale-eating on plants such as yarrows, spurge, sorrel, and plantain.
Once the brightly colored moth caterpillar has metamorphosed into a pupa, it transforms into a hairy brown moth with strongly speckled patterns on its forewings.
The moth has delicate white hind wings, contributing to its graceful and alluring appearance when in flight.
The immature stage of the sweet gale moth caterpillar can be identifiable by the orange stripe that runs along its flanks and the light gray band that runs along its back. In addition to that, it has numerous tufts of spikes.
6. Erasmia Pulchella
The body of the Erasmia pulchella caterpillar is covered in spikes and has a shiny appearance; it also has a yellow patch on the back and red dots on the sides.
The Erasmia pulchella caterpillar is a huge tropical caterpillar with spikes native to Southeast Asia. It is coated in hair and has yellow patches in the middle of its back.
Along the sides of its body, the shiny caterpillar also has red growths and white spikes.
The caterpillars of the Erasmia pulchella species have a more oval morphology than the slender, worm-like shape typical of most spiky caterpillars.
The green, yellow, and spiky red caterpillar most often feeds on shrubs and plants of Helicia, native to Southeast Asia.
These Spiky caterpillars are not poisonous; they release a poisonous hydride compound from the tubercles on its body when disturbed.
This putrid substance is a natural defense against scavengers and other hungry animals.
When it emerges from its pupa, the Erasmia pulchella is a gorgeous, multicolored moth with bright white, deep red, and iridescent blue patterns.
On the other hand, the color hue of the wings can shift depending on the location and climate in which the moth lives.
The Erasmia pulchella caterpillar is a shiny caterpillar that the brilliant yellow patch may recognize on its back, the red growths that run along its abdomen, and the hairs that emerge from tubercles.
7. Sycamore Tussock Caterpillar
The sycamore tussock caterpillar (Halysidota harrisii) is an odd-looking white caterpillar covered in spikes. A pair of prominent spike pencils emerge from both ends of its body.
The head and body of the caterpillar are both covered in white bristly spikes and have a yellow-orange coloration.
If you pick up these spiky caterpillars, the prickly tufts on their back might irritate your skin, although the bug does not sting.
The caterpillars of the sycamore tussock moth feed on the American sycamore tree, and the caterpillars eventually metamorphose into moths.
The body of the sycamore tussock caterpillar is spiky and white. It has two long orange pencil spike tufts at one end and two at the other.
These caterpillars, measuring up to 1.1 inches long, are coated in tiny spikes (30 mm).
8. American Dagger Caterpillar
The American dagger caterpillar (Acronicta Americana) is a yellow caterpillar with a spiky appearance. It is coated in long, wispy spikes of pale yellow.
The head of this fuzzy worm is spherical and shiny black, and it has two pairs of long black tufts on its belly.
These are both distinguishing traits. The prickly body of the non-venomous caterpillar has the potential to irritate the skin.
Even though these spiky caterpillars do not produce venom, the American dagger caterpillar has a sensation similar to being stung.
The itchy, bristly yellow spikes can break off and pierce the flesh if they get close enough.
Between July and October, you can find American dagger caterpillars feeding on the leaves of oak, birch, elm, and maple trees.
Following metamorphosis in the pupal stage, the caterpillar emerges as a gray American dagger moth.
The American dagger caterpillar is easily identifiable by its shaggy-looking body, pale yellow color, and pairs of long black setae on its back.
9. Sycamore Moth Caterpillar
The caterpillar that transforms into the sycamore moth (Acronicta aceris) is recognizable thanks to its spiky yellow body, brilliant orange tufts, and white dots on its back.
The orange-yellow caterpillar of the sycamore tree has a small body, six pairs of prolegs, and a black head.
Caterpillars of this type do not possess stingers and can grow up to 1.5 inches (40 mm) long. They feed on horse chestnut and sycamore trees.
The most distinguishing characteristics of the sycamore moth larva are the pyramidal tufts of orange-yellow spikes that run along its back and the row of white dots that run along its sides.
10. Milkweed Tiger Moth Caterpillar
Because of the black, white, and orange hairy tufts covering its body, the caterpillar of the milkweed tiger moth (Euchaetes eagle) has a very unusual appearance, resembling a worm with spikes.
As it develops into adulthood, the spiny bug, also known as the milkweed tussock moth, takes on a more orange look. These creatures feed on leaves and have spines up to 1.3 inches long (35 mm).
Caterpillars with black and orange spikes can cause significant damage by skeletonizing the leaves of milkweed and dogbane plants.
In addition, the chemicals they take in from the milkweed sap make these spiky caterpillars toxic to birds and other animals that eat them.
The milkweed tiger moth caterpillar is identifiable by the black, orange, and white tufts covering its body.
11. White-marked Tussock Caterpillar
On this list of spiky caterpillars, the white-marked tussock caterpillar (Orgyia leucostigma) stands out as one of the more peculiar examples.
The yellow and black woolly worm is long and slender, with multiple red dots and long pencil spikes at both ends of its body.
Four white toothbrush tufts cover its back. The caterpillar’s black and yellow stripes on its body make it easy to recognize.
The odd-looking caterpillar has spiky tufts, each with a small barb that can penetrate the skin and cause an infection.
When handled, the caterpillar can give off a stinging feeling, although it does not sting. This creepy-crawly creature is a caterpillar and can be found all around Florida.
The white-marked tussock caterpillar is easy to identify due to the four bushy and prominent white tufts on its back, the yellow stripes running down its body, and the wispy white and black spines wrapped around its body.
12. Southern Flannel Moth Caterpillar
The larva of the southern flannel moth (Megalopyge opercularis) is a brown caterpillar with a hairy exterior covered in sandy-brown spikes.
The appearance of these spiky caterpillars is deceiving because, although they appear soft, the spikes hide spines loaded with venom.
The stinging caterpillar is around 1 inch (25 mm) long and can be light brown or dark gray.
The southern flannel caterpillar is also known as the puss moth, the Italian asp, the fire caterpillar, the woolly slug, and the asp caterpillar.
These names come from the caterpillar’s velvety, opulent appearance and stinging behavior.
The caterpillar of the southern flannel moth is easily recognizable by the soft, ruffled, golden-brown spikes that cover its body.
13. Yellow Woolly Bear Caterpillar
The slug-like yellow woolly bear caterpillar (Spilosoma virginica) derives its name from the bronze-brown tufts covering its body.
The caterpillar’s soft and fuzzy appearance is due to the golden or yellowish-brown woolly spikes covering its body.
The caterpillar can be black, orangey-red, or dark yellow and grow up to 2 inches (50 millimeters) long.
The color of the caterpillar depends on the environment in which the larva develops.
Like the spikes on most other spiky caterpillars, the spiny spikes don’t sting or contain any venom.
When handled without gloves, the spiny tufts, however, have the potential to cause localized skin discomfort.
14. Garden Tiger Moth Caterpillar
The Garden Tiger Moth’s caterpillar stage (Arctia Caja) resembles a huge, spike-covered black and orangey-brown caterpillar.
Because of its lengthy black and dark gray spines, the caterpillar resembles a hedgehog or porcupine.
If you pick up one of these caterpillars, the barbed spikes might damage your flesh, even though it appears soft and spiky.
Caterpillars of the Garden Tiger Moth harm birds and other animals that eat them.
These enormous “woolly bears” eventually metamorphose into beautiful moths with black, white, and orange patterns on their wings.
The Garden Tiger Moth is simple to recognize because of its spiky body, which is black and orange, and long, grayish-colored spines.
15. Walnut Caterpillar
The walnut caterpillar (Datana integerrima) is a spiky black caterpillar coated in long, wispy whitish-gray spines.
These spiky caterpillars are not dangerous to people, and their prickly covering will not irritate your skin if you handle it.
The fuzzy black caterpillars grow to be around 1.1 inches (30 mm) long and have a cylindrical shape with a slender profile.
One characteristic that distinguishes walnut caterpillars from other types is their tendency to congregate in large groups.
While feeding on pecan, butternut, hickory, and walnut trees, These spiky caterpillars can sometimes blanket branches with wiry spikes as they strip the leaves from the trees.
The walnut caterpillar’s slender, worm-like black body is coated in small spikes, which give it a fuzzy look and make it easily distinguishable from other caterpillars.
15. Monkey Slug Caterpillar
You’ll encounter one of the most peculiar and spiky caterpillars, the monkey slug caterpillar (Phobetron pithecium).
The fuzzy brown larva, also known as the hag moth caterpillar, is unique among caterpillars.
The golden-brown slug looks like a squashed spider because it has 18 spiky spikes running along its body.
The length of a monkey slug caterpillar ranges from 0.6 to 1 inch (15 to 25 mm). It is possible to have an allergic reaction and experience significant skin irritation from the dark tan spikes that cover the caterpillar’s body.
No other kind of caterpillar even comes close to resembling the monkey slug caterpillar, regardless of whether or not its spikes are present.
This brown caterpillar with a shaggy appearance has nine protrusions that seem like curling brushes.
16. Salt Marsh Moth Caterpillar
The salt marsh caterpillar (Estigmene acrea) resembles a brown moth larva with sharp-looking spines protruding from its body.
It is also known as the salt marsh spittlebug. Despite its appearance, the bristles are gentle and will not cause discomfort.
However, after handling one of these caterpillars, your skin may start to itch due to the irritating setae on many spiky caterpillars.
The body of these spiky orange-brown caterpillars is cylindrical and fat, measuring 2 inches (50 millimeters) in length.
A further distinguishing feature of the segmented larva is a series of orange warts, each with a white dot in the center.
The caterpillars with dark spikes love soya bean, cabbage, cotton, and tomato plants.
The salt marsh caterpillar is a thin, dark brown bug with spikes all over its body and a series of black and orange dots along its abdomen.
17. Hickory Tiger Moth Caterpillar
It is possible to recognize the spiky white caterpillar by the diamond-shaped black stripes that run along its back.
These spiky caterpillars (Lophocampa caryae) are also known as the hickory tussock moth caterpillar.
This fuzzy insect also has tufts of black pencil spikes and a rounded, shiny head, characteristics shared by many tussock caterpillars.
This spiky caterpillar is black and white and 1.7 inches (45 mm) long. Caterpillars of the Hickory Tiger Moth have barbed spines.
Even though they appear to be soft, the spikes have the potential to become embedded in the skin, resulting in discomfort that can range from mild to severe.
Pecan, walnut, hickory, willow, and other ephemeral trees are among the foods the white-furred larvae consume.
The caterpillar stage of the Hickory Tiger Moth is identifiable by its white coloration and unique black markings.
18. Yellow Spotted Tussock Moth Caterpillar
Because of its unusual black and yellow colors, the larva of the spiky yellow-spotted tussock moth (Lophocampa maculata) stands out from the crowd.
The yellow caterpillar has long tufts of vivid white spike pencils and pointed back ends resembling jets. Due to its striking yellow and black coloration, it is easy to detect.
Because of the fuzzy look of the adult moth, the caterpillars of the yellow-spotted tussock moth are also called the ‘yellow woolly bear.’ The length of the tussock caterpillar is around 1.1 inches (30 mm).
Because it is clothed in yellow and black spikes and has tufts of white lashes on its head and rear end, the larva of the yellow-spotted tussock moth is very easy to identify.
19. Fall Webworm
The fall webworm (Hyphantria cunea) is a white or pale yellow caterpillar with filaments all over its body.
The spiky white autumn webworm is known for its unique activity, which involves building structures that resemble tents and are inhabited by swarms of crawling larvae.
The spherical, shiny black or redheads of fall webworms are another distinguishing feature of these insects.
The huge nests that fall webworms build dangling from the branches of trees make them very easy to notice.
The fuzzy white larvae spend most of their lives in the web tents, where they develop to be 1.37 inches (35 mm) long.
After the pupation process, the long, spiny bugs transform into beautiful white moths.
The thread-like spikes adorn their slender black or dark brown bodies, which are the distinguishing characteristics of the fall webworm.
20. Pale Tussock Moth Caterpillar
The pale tussock moth caterpillar (Calliteara pudibunda) is a peculiar-looking caterpillar covered in spikes, with a coloration between yellow and green.
The characteristic tufts that run along the back of all tussock caterpillars are also visible on the fuzzy larva.
These spiky caterpillars are yellowish-green and have a prominent tuft of reddish-colored lashes at one end. When folded up, the caterpillar shows a pattern of black stripes.
The huge yellow and pale tussock moth caterpillar is 40 to 45 mm 1.5 to 1.7 inches long.
Depending on the instar, the spiky caterpillar might have a reddish, pale brown, or greenish coloration. On the other hand, yellow and green are the most common colors.
The brilliantly colored pale tussock moth has toothbrush-like tufts of bright yellow setae, black bands, and a jutting tuft of spike pencils at the rear end of its body.
21. Fox Moth Caterpillar
The larva of the fox moth (Macrothylacia Rubi) has a brilliant orange back with black spikes all over its body.
The length of the fuzzy black and orange caterpillar can reach up to three inches (eight centimeters).
The black fox moth larva matures into a beautiful moth with a huge, tan body covered in fur.
Caterpillars of the fox moth eat on birch trees, willows, and other members of the willow family and plants in the bean family. They also feed on flowering perennials and tiny shrubs.
The fox moth caterpillar is easily recognized by its spikey, black body and the brilliant orange patterns that run along its back.
22. Virginia Ctenucha
The Virginia ctenucha (Ctenucha virginica) caterpillar has spikes that are white and tufts that are yellow.
This gives the fuzzy larva the impression of being creamy white. In addition to its spiky exterior, the spiky caterpillar has a redhead and scarlet red prolegs.
The white caterpillar is quite simple to detect when contrasted with the greenery. These spiky caterpillars can develop to a length of between 0.8 and 1 inch (20 – 25 mm).
After pupation, the bright and spiky caterpillar transforms into a wasp moth among North America’s largest.
It is important to remember that during some stages of its life cycle, this species’ caterpillar looks like a spiky black caterpillar with a white stripe running along each side.
The Virginia ctenucha caterpillar is easily identified because of the white and yellow tufts of spikes covering its slender body.
