Do hornworms bite or sting? Can they hurt humans, and what care should you take to handle them? Here are all the answers.
Hornworms are large insects, almost 4 inches long, and have a stinger-like horn on their backs. These two characteristics have given them a bad reputation, and many people fear having to touch them.
In this blog, we look at how dangerous hornworms really are. Do hornworms bite? Do they sting? What can happen if one bites you? We answer all of these questions.
Can Hornworms Bite?
Hornworms can bite, but the bite is hardly anything to talk about. These large worms don’t have teeth or strong mandibles.
Even though they might try to bite you, the best that they can do is to startle you. You won’t feel any pain, and neither will the bite leave behind an injury.
Do Tomato Hornworms, Tobacco Hornworms, Green Hornworms Bite?
All hornworms can bite. However, neither of them can bite you hard enough to make any impression on you, apart from a slight, startling sensation.
Tobacco and Tomato hornworms are two different species of hornworms, and there are quite a few differences between the two.
They have different physical characteristics. Tobacco hornworms have a curved, red-colored horn at the back and the diagonal stripes on their body lean backward. The horn on the Tomato hornworms does not curve, and its stripes are V-shaped.
Tomato hornworms feed on only nightshade plants such as eggplant, potato, pepper, and obviously tomato plants. Tobacco hornworms also feed on the same plants but prefer tobacco plants as well. Both species chew up the leaves and sometimes even the fruits of their host plants.
Do Hornworms Sting?
No, hornworms do not sting. This is a common misconception because of the horns on their backs, but the horn is not strong enough to act like a stinger.
Even if the hornworm pricks against your skin, you won’t feel much because it is not hard or sharp like other bugs’ stingers.
Do Hornworm Bites Hurt?
No, they don’t hurt. Like we said before, the worst that can happen is that you will get startled and might drop the hornworm from your hand.
You may feel a bit queasy, but the truth is that the hornworm does not have a strong enough jaw to cause any serious damage. As a fun fact, the hornworm’s jaws make a clicking sound that is supposed to ward off predators.
Are Hornworms Dangerous/ Poisonous to Humans?
Once again, the answer is no. Hornworms are completely harmless to humans. They don’t carry any venom or poison, and moreover, since they don’t have the wherewithal to penetrate human skin, any venom that they might have had would still have been useless.
Unfortunately, the same is not true for your pet. We talk about that in the next section.
Are Hornworms Dangerous To Pet Animals?
Yes. Hornworms store toxins in their body that can be dangerous to most pests. These toxins come from the tobacco and tomato plants these critters eat.
This means that wild hornworms are a strict no-no when it comes to your pets’ chow time. However, if you buy hornworms from a reputed breeder, those will not carry any toxins.
Moreover, you can easily identify them because they are blue-colored instead of the normal green-colored ones you find in the wild. Let’s talk more about different pets and which are safe from a hornworm:
Dogs and Cats
Both pet dogs, as well as cats, should never be given hornworms that you have plucked from the wild. These insects contain harmful toxins within them, which can be poisonous to your dog or cat.
Chickens
Chickens are much harder than dogs and cats. Chickens feed on insects all the time, so they have built defense mechanisms in their stomachs to ward off the poison from insects like hornworms.
Birds
Most birds are fine eating hornworms. Birds like downy woodpeckers, bluebirds, Baltimore orioles, sparrows, and flycatchers love a big, fat juicy hornworm any day. However, most birds prefer smaller hornworms, which are easier to digest.
Bearded Dragons
Yes, both bearded dragons and leopard dragons love hornworms! These worms don’t have any chitin in them, so they are not dangerous for your geckos, lizards, and similar animals.
Make sure that you feed only the smaller hornworms to your baby bearded dragons. For the adult ones, you can feed one to two hornworms twice a week.
Who Preys on Hornworms?
In the wild, one of the predators of the hornworm is the Braconid wasp. These beneficial insects lay their eggs on the hornworm, and when the wasp larvae come out, they eat up the poor hornworm as food. Paper wasps are also similar predators of hornworms.
Frequently Asked Questions
Do hornworms have teeth?
No, hornworms do not have teeth. They do have mandibles. They can open and shut their mouths and make a clicking sound by using these mandibles (which might sound like the clicking of sharp teeth).
But they do not have any teeth, and for this reason, they cannot cause much pain while biting you.
What do hornworms turn into?
Hornworms grow into adult moths. Specifically, hornworms grow into the sphinx, hummingbird or hawk moth. There are four main stages in its life:
- Egg
- Larva
- Pupa
- Moth
Once the hornworm enters the pupa stage, its body begins to harden, it gains weight and becomes a large green caterpillar, thus readying itself to come out of its shell as a moth finally.
Do hornworms have eyes?
Yes, hornworms do have eyes. But more interestingly, they have a unique adaptation: they have a large number of fake eyes spread all across their bodies.
These fake eyes might deter and predator planning to attack the hornworm by simply looking intimidating.
The actual eyes of the hornworm are on the inside of its head, hidden away.
Can hornworms bite my bearded dragon?
No, it cannot bite your bearded dragon. The poor hornworm has no teeth to speak of, and the bearded dragon is sure to make short work of it because hornworms are typically slow movers, large in size, sweet in taste, and easy to capture.
In fact, many bearded dragon owners use hornworms as feeder insects for their beardies.
Wrap Up
Hornworms may look menacing, but that’s all a camouflage for a relatively harmless little insect that can neither bite nor sting you to protect itself.
However, if you want to use the hornworm as a feeder for your pet, make sure that it is suitable for your pet and is not toxic. Never feed your pet a hornworm from the wild because it might have toxins in it. Thank you for reading!
Reader Emails
Over the years, our readers have sent us several emails on this topic. Please go through them below.
Letter 1 – Hornworm from Mexico
What is this specimen?
Geographic location of the bug: Yucatan, Mexico
Date: 09/01/2017
Time: 10:54 AM EDT
Saliendo del trabajo me encontré con esta fea, chistosa, rara especie y ante el temor de ver mas de estos mejor asesorarme y saber que tipo es y si es venenosa o peligrosa de alguna forma.
How you want your letter signed: Luis Alamilla
Hola Luis,
This is a harmless Hornworm, the caterpillar of a moth in the family Sphingidae. All of its caracteristics, the false eyespots, the caudal horn, the ability to retract its head causing it to look like a snake are are mimicry tricks to make it seem much more dangerous than it is. We will attempt to provide you with a species name.
Letter 2 – Hornworm from Morocco
Subject: Varition of Morocco horned caterpillar color
Geographic location of the bug: Closest to Erfoud, Morocco
Date: 10/08/2019
Time: 10:49 AM EDT
Your letter to the bugman: Hello BugMan! I wanted to show you this variation in color of the (perhaps) Barbary Spurge? Hornworm.(OR tell me the exact ID; I see some with two dots!) We found these while riding camels in Erg Chebbi sand dunes on the vegetation shown. We gently tickled one and put him on a leaf to better photograph. Then we put him back on leaves. There were LOTS of them! They can make their way quite fast over the sand when looking for another bush! I took the photos on September 26, 2019. Thank you!
How you want your letter signed: Cynthia S.
Dear Cynthia,
This hornworm is definitely from the genus Hyles, but we cannot be certain of the species. It does look most to us like the Barberry Spurge Hawkmoth caterpillar pictured on Sphingidae of the Western Palaearctic.
Letter 3 – Hornworm from New Guinea
Please help me ID Snakie -Giant Caterpillar
Location: Port Moresby, Papua New Guinea.
July 5, 2011 2:04 am
Dear Mr.B.,
I found this snakeike creature in the yard. it is about 6-inches long, with contrastng brown and black colours , resembling and behaving like a snake. I don’t know if this was just me or my anti-snake/spider ’sensors’ going off, but I jumped a bit at first.
It was found this July in tropical environment, with mediterranean/savannah like environment, but in recent rainy wearher. I am located in Port Moresby in (Papua) New Guinea. I just hoped somone could assist. This is the largest caterpillar I have ever seen until your wb page about the French caterpillar.-July 2011. I am not a collector but curious and scientifically minded.
Anyway thanks for your attention. . –
Signature: Nick.L
Hi Nick,
While we are unable to determine the species at the moment, we can tell you that this Hornworm is the larva of a Sphinx Moth or Hawkmoth in the family Sphingidae.
Letter 4 – Hornworm from Paraguay
Subject: What kind of caterpillar is it?
Location: Asuncion, Paraguay
April 1, 2016 9:59 am
Hi! I found this caterpillar in my backyard, is almost 5 inches long, the horn on the tail is grey-ish, it has small little hairs all over but very little in cuantity too, small brown/yellow spots, and a white line on the back that connects both sides of it with the horn…
I’ve tried to find on the Internet one that looks exactly like that one, there are a few ones that look a bit alike but there is not an exact match, and I know every detail counts.
Signature: Thank you guys so much!
We believe this Hornworm in the family Sphingidae is Cocytius antaeus based on images posted to Bizland. We will contact Bill Oehlke for verification. We suspect he may request the use of your images for his site if you will allow. Do you know the type of tree the Hornworm was feeding upon?
No problem, use the images how ever you guys want! And the tree is a custard apple tree… and again thank you guys!
Bill Oehlke Concurs
Daniel,
Yes, It is Cocytius antaeus. It is also nice to know specific location at least one level below national level, the more specific the better.
Thanks for thinking of me.
Bill
Letter 5 – Hornworm from South Africa is Clearwing Hawkmoth
Hornworm…but what is it’s name?
December 17, 2009
Hey, just came back from a trip to Hluhluwe Game Reserve in Northern Natal, South Africa. I found this hornworm hanging around in the low foliage. Your site directed me to hornworms, but I can’t find a name for this specific one. Any help? Thanks, great site!
Etienne Fourie
Northern Natal, South Africa
Dear Etienne,
Sadly, we don’t know the species of your Hornworm. We are copying Bill Oehlke on our reply. He may be able to assist in the identification of this Hornworm in the family Sphingidae. Hopefully, he will know the answer and he will inform us both as to the identify of this lovely Hornworm.
Letter 6 – Hornworm from Suriname: Cocytius antaeus
Subject: Big Green Caterpillar From Suriname
Location: Surinamese interior, South America
July 1, 2012 12:29 pm
Hello Bugman, I was hoping you could help me identify a particular caterpillar I photographed when living in Suriname, South America about ten years ago. Is it a Tobacco Hornworm of some kind? My only source is ”Insects of Suriname” by Maria Sibylla Merian and her illustrations are over 200 years old, so I can’t be sure. Suriname doesn’t have any seasons, apart from Rainy vs. Dry, but I can tell you I took this picture in the Rainy season. Thanks in advance!
Signature: Brian
Hi Brian,
You are correct that this is some species of Hornworm in the family Sphingidae, however, it is not a Tobacco Hornworm. Though Maria Sibylla Merian’s book is awesome, it is not ideal for identification purposes. You can try browsing the 100 or so species on the Sphingidae of the Americas Suriname page to get an identification. If you get the answer, please write back to us.
Hello, very interesting caterpillar! It looks very much like the dark form of Acherontia lachesis. This form occurs in all the three known Acherontia species, like in A. atropos, but also in the genus Coelonia from Africa and Madagascar. If I am wrong and this is not Acherontia lachesis, it may be a caterpillar of a species from a closely related genus of the Sphingini-tribe, eg. a Megacorma species, which are officially not yet known or described…
Best wishes from Berlin,
Bostjan
I’d just like to revise myself – it IS an Acherontia lachesis, of course; why should a caterpillar of another genus in this region be that similar? Its colour, shape and horn completely correspond. The greenish yellow color variation with blue stripes is much more usual and better known, like in its western relative A. atropos; when the larva is about to pupate, its green and yellow colors turn to orange, but the lateral stripes remain bluish, whereas the brown and grey nuances in the present type of pattern on the photo do not change at all. The caterpillar was on its pupating trip, and therefore found when walking on the ground; they dig themselves deep into moist soft soil (down to 50 cm), just like in Agrius, Manduca or Cocytius, to burrow there an egg-shaped hole and to pupate in it – the soil must be of brown mineral type, as they don’t like humus and would get infected. It is relatively difficult to find a corresponding place of humid (but not wet) and adequately tender soil under everyday conditions, and this is the weak point of all Acherontini tribes – which, therefore, are often forced to seek or wait for a long period to find it; most of the widespread, well-known species from these genera are migrants, which originally lived in much restricted areas. And caterpillars of the most of them prefer to feed on annual plants requiring fresh soft soil, and this is generally to be found on bluffs and after landslips – and of course, in cultivated areas, where soil is being agriculturally treated, just to grow those plants. (That’s why Manduca sexta and Manduca quinquemaculata, the classical american “hornworms” are that spread in the New World; plants of the family Solanaceae (like potato and tomato, peppers and tobacco) primarily grew on a few points, but got wide-spread by man; the most of edible and applicable kinds of this plant-genus, highly branched in the New World, originate from there – an exception is the eggplant (Solanum melangena), coming from India. The Manduca species are often the only pollinators of the american Solanaceae, which therefore open their long chaliced blossoms at night only – like the Nicotiana (tobacco) and the Datura (jimson weed); this is similar in Coelonia and Xanthopan from the African area, but, the larvae of the latter only live on the tree genus Annonaceae, like the most species of the neotropical moth genus Cocytius, and the Asian Meganoton.)
As soon as potatoes were introduced in Europe, the larvae (ie female moths) of Acherontia atropos – which were formerly predominantly found on Oleaceae (like privet, Ligustrum, olive tree, Olea, jasmine or ash, Fraxinus) showed a clear preference for this plant. The gorgeous caterpillar is well known in its usual, yellowish green, blue striped pattern type… and less in the much more rare greyish brown one. Like that of Manduca and Agrius, its big pupa is of reddish brown color, but has no proboscis case at all.
The beautiful moth is very massive, of a dark brown basic color with some bluish shine and whitish points and spots; there is an impressive skull-like pattern of light hair on its thorax, reminiscent of a “deads head”, which led to its popular name. In the eastern species A. lachesis, the light whitish yellow pattern is additionally reinforced by a fluorescent red. All the three species of the “death-head-hawkmoths” are highly similar; their bodies are dark brown with two lines of dorsal yellow spots – very similar to those in the american Manduca species. However, the most striking difference to those, and to all other species of related genera, is the fact, that they have an extremely short proboscis, which disables them to live from any flower nectar – they are bee-hive visitors instead, drilling the cells and stealing honey. To protect themselves from angered bees, they can produce a strong, effective squeaking noise, which has the same frequency and works like the appeasing sound of a bee-queen – and is very loud and easy to hear by human ears; every of the three moth species is specially adapted to a local dominating kinds of honey bees. Due to this old feeding adaptation, moths of the genus Acherontia are not only vigorous flyers and migrants, but also very strong walkers, finding the smallest holes and clefts to enter and escape from a closed space (whereas all other butterlies and moths can only fly towards a source of light). Additionally, they are very smooth and therefore prettily unseizable for bees, and, as experiments have shown, they even smell like bees. Though, in a case of accident, the huge moth corpse is covered by wax; it is quite heavy and can’t be drawn out by bees, and those “mummified” corpses are sometimes found by bee-breeders. In some areas of Egipt, the moth is even called “Father of the family” – due to an evident misunderstanding; it is supposed to be the male, visiting the queen.
The large caterpillar on the photo may have transformed to a moth in the meantime…
Nice wishes,
Bostjan Dvorak
Thanks so much for this very thorough comment.
This is a Cephonodes hylas caterpillar; this clearwing hawkmoth species inhabits Asia as well as Africa. Its nice caterpillar can be differently coloured, but can always be recognized by the characteristic shape of head and body; it is found on many Rubiaceae – I often saw it on Gardenia bushes in Korea and Japan – and is even said to be a potential pest on coffee in some parts of Africa.
Thank you. We have updated the posting.
Great pictures of a wonderful finding, congratulations!
The leaves look like those of Annona squamosa (custard apple), an indigenous fruit tree, which is sometimes followed by this species of an originally rather rare Cocytius moth into plantations.
Best wishes,
Bostjan Dvorak
Thanks for the comment Bostjan.
Great pictures of a wonderful finding, congratulations!
The leaves look like those of Annona squamosa (custard apple), an indigenous fruit tree, which is sometimes followed by this species of an originally rather rare Cocytius moth into plantations.
Best wishes,
Bostjan Dvorak
Giant sphinx, Cocytius antaeus.
This species typically feeds on trees in Genus Annona.
We don’t know how long this comment has been waiting for approval. We apologize for the delay.
Nice to find this interesting record on this wonderful site, after some years!
It is obviously an almost grown up caterpillar of a Cocytius (/Amphonyx) species on the twig of an Annonaceae plant. According to this coloration with the dark horn, one pair of the lateral stripes and the central line, almost certainly Cocytius antaeus.
Best wishes
Bostjan Dvorak
Thanks for this identification on this old posting Bostjan. Interesting, there is another comment that we missed previously that makes the same identification.
Dear Daniel, Dear Cynthia,
yes, definitely this species (Hyles tithymali ssp). How interesting, it feeds on Euphorbia guyoniana on Your photo. Thank You for sharing!
Best wishes,
Bostjan
Thanks for the confirmation Bostjan.
Dear Daniel, Dear Cynthia,
yes, definitely this species (Hyles tithymali ssp). How interesting, it feeds on Euphorbia guyoniana on Your photo. Thank You for sharing!
Best wishes,
Bostjan
A fascinating region, by the way, even geologically; the Antiatlas is part of the same montaneous system as the Appalachian mountains, much older than the ocean…
Nice wishes,
Bostjan
Yes, the Appalachian Mountains are very old. Daniel hails from the Ohio/Pennsylvania border very near the Appalachian and Allegheny Mountains.
A fascinating region, by the way, even geologically; the Antiatlas is part of the same montaneous system as the Appalachian mountains, much older than the ocean…
Nice wishes,
Bostjan