Tag Archives: scolopendra

Endangered, Bird-eating Centipedes of Mauritius

Can a centipede really be endangered? Of course!

Centipedes don’t get much love, even from each other. They are solitary, irritable, fiercely cannibalistic, and arguably some of the most widely hated animals on earth. I know many biologists who would gladly handle a snake or tarantula, but shudder at the thought of a giant centipede creeping up their arm.

An Indopacific centipede, making good use of a hole in the wall. Photo by Thomas Brown, licensed under CC BY 2.0.

An Indopacific centipede, making good use of a hole in the wall. Photo by Thomas Brown, licensed under CC BY 2.0.

I never begrudge people for being scared of centipedes. They are objectively frightening: many-legged, venomous, fast-moving, and secretive. In the rural tropics, a painful bite from a giant centipede is a very real possibility. But none of this means they can’t be endangered, put at risk of extinction either by natural circumstance or by human activity.

Unsurprisingly, very few centipedes have ever been studied from a conservation-oriented perspective. Most of the time, there simply isn’t the funding, public interest, or lack of squeamishness to make that kind of research happen. There are, however, exceptions. Today I’m going to tell you about one: the giant centipedes of Mauritius and Rodrigues.

Mauritius, Rodrigues, and their satellites form a collection of tiny islands in the Indian Ocean, just a few thousand miles east of Madagascar. Like most islands they have a long, sad history of extinctions wrought by over-hunting, invasive species, and habitat destruction. The dodo bird, native to Mauritius, was one of the first victims.

Mauritius.png

Mauritius, in panoramic view. Photo by Clément Larher, licensed under CC BY-SA 3.0.

The two main islands are home to two species of giant centipede, the blue-legged (Scolopendra morsitans) and the Indopacfic (Scolopendra subspinipes) centipedes*. Both species are incredibly efficient predators, and with body lengths of 8 inches or more, they are more than capable of tackling large prey such as mice. On Mauritius, staple fare include house geckos and cockroaches, but they also take day-old chicks from their nests when opportunity strikes (Lewis et al. 2010). The Indopacific centipede can even swim, undulating side-to-side while holding its head above the surface like a crocodile (Lewis 1980).

Despite their size, venom, and general badassness, giant centipedes are prey for many larger animals. On Mauritius, they form 80% of the diet of feral cats that roam the island by night. The cats are apparently nimble (and daring) enough to tear apart the centipedes without getting bitten.

An Indopacific centipede from China. Photo by Thomas Brown, licensed under CC BY 2.0.

An Indopacific centipede from China. Photo by Thomas Brown, licensed under CC BY 2.0.

Even in the face of predation by cats, giant centipedes remained abundant until 1997, when a new invasive species came into the picture. That species was the musk shrew (Suncus murinus), introduced from India. A smaller shrew might become prey for a centipede, but the musk shrew is the largest in the world, reaching a length of 6 inches or more.

An 8-inch-long centipede is still a formidable adversary, but the shrews were used to encountering giant centipedes in their native range (as it happens, the Indopacific centipede also lives in India). They have made short work of centipede populations, which are now greatly reduced (Lewis et al. 2010). The Indopacific centipede is now found on Rodrigues, but no longer on Mauritius, while the blue-legged centipede is still found on both islands.

Mauritius and its satellite islands. From Lewis et al. (2010), licensed under CC BY 4.0.

Mauritius and its satellite islands. From Lewis et al. (2010), licensed under CC BY 4.0.

I am not about to launch into a passionate defense of blue-legged and Indopacific centipedes. As I said before, both species are abundant in tropical habitats all over the world, from Indonesia to the Caribbean. For all we know the centipedes themselves are invasive, dancing with cats and shrews on the graves of long-gone native species. Instead this article is about another giant, a third centipede, gone from Mauritius but still clinging to life on Serpent Island.

Serpent Island is a satellite of Mauritius, uninhabited by humans and with an area less than 100 acres. There is very little vegetation or soil there, and bare rock dominates the surface. In the absence of humans or large predators, sea birds thrive, especially sooty terns which nest by the thousands on open ground.

They share the space with centipedes — not Indopacific or blue-legged, but Serpent Island giant centipedes (Scolopendra abnormis), which are found on one other satellite island (Round Island) and nowhere else on earth — not even Mauritius. The centipedes are abundant on Serpent Island, with roughly 12 individuals per square meter. If centipedes frighten you, don’t plan your next vacation here.

During the day centipedes hide beneath rocky slabs and underground, away from the light and from watchful, easily enraged mother birds. Terns are active during the day, flying from land to sea and back again, gathering fish for their hungry chicks. With all the traffic, a centipede is better off staying out of sight.

A sooty tern. Photo by Duncan Wright, in public domain.

A sooty tern. Photo by Duncan Wright, in public domain.

By night the terns are less wary. Snakes, which would normally prey on tern chicks, are absent from the island, probably driven out soon after the arrival of European explorers. Without the competition, centipedes have risen to take their place. Wandering over the rocks, a centipede uses smell and touch to locate a nest, grab hold of a chick, and sink in its venom-laden fangs. More than any so-called bird-eating tarantula, the Serpent Island centipede is a true bird-eater. In captivity, they can survive for several years on a diet of chick legs (Lewis et al. 2010).

The taste for bird meat is probably a recent acquisition — Serpent Island centipedes most likely colonized the island only a few million years ago. They would have arrived from Mauritius, suggesting the larger island had a population of Serpent Island centipedes before they were driven to extinction by the introduced shrews, cats, and perhaps larger centipedes.

The Serpent Island centipede is classified as Vulnerable by the International Union for Conservation of Nature (IUCN 2012). This means the species is  “considered to be facing a high risk of extinction in the wild.” It is one of 10 potentially threatened centipedes on the IUCN Red List (of 3,300 total centipede species worldwide). So far, none have been given legal protection.

Centipede snacks. Photo by Duncan Wright, in public domain.

Centipede food. Photo by Duncan Wright, in public domain.

The bad news is that, if shrews or cats or rats were to be introduced to Serpent Island, the entire ecosystem would collapse. Invasive predators would quickly eat both chicks and centipedes, leaving Serpent Island a bare rock in the middle of the ocean, with a few tufts of grass and the occasional cockroach.

The good news is that centipedes are abundant in their last remaining habitats, with an estimated population of 10-15,000. Serpent Island is remote and protected, and biologists are pretty much the only visitors, so it is unlikely shrews will ever get there. The future of Serpent Island’s bird-eating centipedes is secure, for now.

Reminder: there are still 6 days left to donate to Dr. Adam Britton’s crowdfunding campaign to study threatened pygmy crocodiles in Australia! I’ve donated, and I encourage you to so if you think pygmy crocodiles, which you can read about here, are awesome, which of course they are. There are some amazing prizes for donors, including crocodile-themed artwork and jewelry!

*These species normally go by the common names Tanzanian giant (blue-legged) and Vietnamese giant (Indopacific). However, both are extremely wide-ranging in tropical habitats all over the world, including Hawaii where they have been introduced by humans (Shelley et al. 2014). To reduce confusion I used alternative common names.

Cited:

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. Gland, Switzerland and Cambridge, UK: IUCN. iv + 32pp.

Lewis J.G.E., P. Daszak, C.G. Jones, J.D. Cottingham, E.Wenman, and A. Maljkovic. 2010. Field observations on three scolopendrid centipedes from Mauritius and Rodrigues (Indian Ocean) (Chilopoda: Scolopendromorpha). International Journal of Myriapodology 3: 123-137.

Lewis J.G.E. 1980. Swimming in the centipede Scolopendra subspinipes Leach (Chilopoda, Scolopendromorpha). Entomologists Monthly Magazine 116: 219-220.

Shelley R.M., W.D. Perreira, and D.A. Yee. 2014. The centipede Scolopendra morsitans L., 1758, new to the Hawaiian fauna, and potential representatives of the “S. subspinipes Leach, 1815, complex” (Scolopendromorpha: Scolopendridae: Scolopendrinae). Insecta Mundi 338: 1-4.

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North America’s Big Five Centipedes

When Halloween comes around, snakes and spiders tend to steal the show. Yet centipedes, in my experience, tend to evoke even stronger reactions from people — I have met many entomologists who would happily handle a tarantula but recoil in horror when faced with a giant centipede.

In the United States there are five species of giant centipedes in the family Scolopendridae. Today, in the spirit of Halloween, I give you the Big Five: where they are found, what they do, and why I love them.

Blue Tree Centipede (Hemiscolopendra marginata)

The blue tree centipede. Photo by Sharon Moorman.

The blue tree centipede. Photo by Sharon Moorman.

This is the smallest of the five, seldom exceeding 3 inches, but still the largest centipede throughout most of its range. It is found through much of the East, from Ohio and Pennsylvania south to Florida and west to eastern Texas. Tree centipedes are also found in Mexico south to the Yucatan Peninsula. As the name suggests, the tree centipede is often an attractive blue-green, with yellow legs and orange fangs. The brightness of the color depends on the location, however, and some are paler than others.

The blue tree centipede is a habitat specialist, living under the bark of rotting trees, often before they have toppled to the ground. I have had the best luck finding them under the bark of pine logs. Because they are such good climbers, they occasionally wind up in buildings where they can cause quite a scare.

Bites from tree centipedes are painful but not much worse than a bee sting. They use their venom, as all centipedes do, to kill prey. Because they prefer to live in rotten pine logs, they may specialize in hunting beetle grubs that eat rotting wood. Like most centipedes, however, data on their feeding habits is severely lacking.

Green-striped Centipede (Scolopendra viridis)

The green-striped centipede is larger, reaching 6 inches or so, and usually pale yellow with a thick green or black stripe running down the back. Other patterns exist, however, and in parts of their range this species can appear more like a tree centipede or a tiger centipede (#4). These are adaptable centipedes, found from Florida west to Arizona, but don’t seem to venture further north than South Carolina.

The green-striped centipede. Photo by Jeff Hollenbeck, licensed under CC BY-ND-NC 1.0.

The green-striped centipede. Photo by Jeff Hollenbeck, licensed under CC BY-ND-NC 1.0.

Green-striped centipedes can live in a variety of habitats but they seem to prefer sandy forests. In Florida they can be found in scrub habitat, but like all centipedes they are not well-adapted to drought, and must stay moist by hiding underground or in rotting logs during the day.

Caribbean Giant Centipede (Scolopendra alternans)

The Caribbean giant is the only one of the Five with the russet-brown, mono-chromatic appearance of a “typical” centipede. It is probably our largest species, with a length easily exceeding 8 inches. However, the Caribbean giant is, as you might have guessed, a tropical centipede, and in the U.S. it lives only in southern Florida. It requires humid habitats, and the best place to find them is in and around the Everglades, in Dade and Monroe Counties.

A certain foreign species, the Vietnamese giant (Scolopendra subspinipes), is easily confused with the Caribbean giant at first glance. That wouldn’t be a concern, except that the Vietnamese giant has already become invasive in Hawaii and — this is just my speculating — is likely to become established in the Everglades at some point in the future. Because it is so large, often exceeding 10 inches, the Vietnamese giant is sometimes sold in the pet trade. Bites from either species are not deadly, but extremely painful.

Tiger Centipede (Scolopendra polymorpha)

A tiger centipede from Arizona. Photo by Sue Carnahan, licensed under CC BY-ND-NC 1.0.

A tiger centipede from Arizona. Photo by Sue Carnahan, licensed under CC BY-ND-NC 1.0.

Like the green-striped centipede, the tiger is a 6-inch-long animal found in a variety of habitats. Unlike the green-striped, this is a strictly western species, found from Idaho south through California into Mexico, and east all the way to Missouri. Its name comes from its color pattern: each segment is orange or yellow with a narrow, dark band.

Giant centipedes often move faster by undulating in a snake-like fashion, taking advantage of their long and muscular bodies. When a tiger centipede does this, the bands appear to “flicker,” rather like the brightly-banded milk snake and coral snake. This can make the centipede more difficult to track visually, and hence more difficult for a bird or mouse to grab.

Tiger centipedes, like their namesake, are voracious predators. They have been seen taking down prey much larger than themselves, including geckos and praying mantises. In turn, tiger centipedes are prey for scorpions, spiders, snakes, and many other predators.

A tiger centipede, fallen prey to a scorpion. Photo by Jasper Nance, licensed under CC BY-NC-ND 2.0.

A tiger centipede, fallen prey to a scorpion. Photo by Jasper Nance, licensed under CC BY-NC-ND 2.0.

Centipedes are adapted to moving fast, and their exoskeletons are thin and flexible. The drawback is that they dehydrate very easily. Although tiger centipedes are found in deserts, they still have to remain underground most of the time to conserve moisture.

Giant Desert Centipede (Scolopendra heros)

If you’ve ever seen centipedes used in a horror movie, they were probably heros*. They are big, reaching 8 inches or more. They are also brightly colored in black and orange — perfect for Halloween!

The Arizona form of the giant desert centipede. Photo by Aaron Goodwin, licensed under CC BY-ND-NC 1.0.

The Arizona form of the giant desert centipede. Photo by Aaron Goodwin, licensed under CC BY-ND-NC 1.0.

Heros are found in the desert Southwest, and color patterns vary by location. In eastern Texas and Oklahoma, they are typically jet-black with a bright orange head and yellow legs. In Arizona (above) they are usually red, with the first and last segments black. In New Mexico and western Texas the pattern is orange with black bands, much like a tiger centipede.

A giant desert centipede. Photo from NMNH Insect Zoo, licensed under CC BY-NC 2.0.

A giant desert centipede. Photo from NMNH Insect Zoo, licensed under CC BY-NC 2.0.

Why have black on just the head and the last segment? This an example of automimicry, in which one part of an animal’s body mimics the other. In this case, the tail-end of the giant desert centipede mimics its head-end. When faced with a giant centipede, predators usually attack the head, hoping to avoid a painful bite. If a predator gets confused, however, and attacks the tail instead, an unpleasant surprise awaits when the true head whips around to greet its attacker.

Centipedes, giant and otherwise, are pretty scary, and I never begrudge people who are afraid of them. Still, centipedes are amazing animals and if you see one, I encourage you to take a closer look. It will teach you, if nothing else, that just because an animal is frightening does not mean it can’t be beautiful.

*There is a centipede in one of the Human Centipede movies. People often tell me this after I tell them I study centipedes, so let me clarify a few things: I don’t know what kind of centipede the bad guy has for a pet. Not because I couldn’t identify it, but because I have never watched those movies and never will. I also don’t want to hear you describe your favorite scene with as many details as possible. Thank you.

Samara’s Centipedes

by Joseph DeSisto

Although I am interested in all sorts of creatures, I specialize in centipedes, and after having several conversations to this effect, there are a few things I would like to clear up. No, I haven’t seen The Human Centipede. No, I don’t want to. And no, I don’t want to listen to you describe the plot in excruciating (or really any) detail.

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Scolopendra polymorpha. Photo by Matt Reinbold.

That said, I do enjoy well-made, less grotesque horror movies. The other night I watched The Ring, directed by Gore Verbinski (2002), and I’m pleased to report it’s my new favorite movie featuring a centipede.

Admittedly, the centipede’s two appearances are brief, but to be fair, centipedes don’t make for very complex characters. Near the start of the movie, the protagonist (played by Naomi Watts) watches a tape with a number of horrifying images, including a short clip of a centipede emerging from beneath a table. The tape is in black-and-white, but the size of the centipede places it in the family Scolopendridae, and the striking banded pattern suggests it almost certainly belongs to the species Scolopendra polymorpha.

If any centipede genus deserves a role in a horror classic, it’s Scolopendra, and not just for a Latin name which, let’s be honest, is pretty bad-ass. S. polymorpha in particular is found in xeric habitats through much of the western United States and northern Mexico. Beautifully adorned in bands of black, red-orange, and yellow, this 6-inch-long bruiser is one of the top predators in the dark, damp underground of North America’s deserts. Their main prey are other arthropods, which they kill with a powerful neurotoxic venom.

Across the world’s tropics and subtropics, giant centipedes in the genus Scolopendra prey on pretty much everything they can fit between their poison injecting front claws. This can include all sorts of invertebrates, as well as vertebrates, including lizards, snakes, frogs, and mice. In Venezuela, S. gigantea, a 10-inch-long behemoth, has been recorded hanging upside-down in caves and, snake-style, snatching unfortunate bats out of the air (Molinari et al. 2005). Despite being formidable, they are also prey themselves. In the southwestern U.S. desert, S. polymorpha has been recorded as prey for the much smaller but highly venomous scorpion, Centruroides sculpturatus (Graham and Webber 2013). Scorpions are hugely important predators in deserts, and they may be one of polymorpha‘s main predators.

Although a bite from a giant centipede can be extremely painful, their venom may have practical applications, especially in medicine and medical research. A study by Yang et al. (2013) demonstrated that a particular protein found in the venom of the Chinese Scolopendra subspinipes mutilans inhibited pain in mice. The protein apparently uses the same molecular pathway as morphine, but with greater efficiency.

Scolopendra subspinipes mutilans, from China. Photo by Yasunori Koide.

Scolopendra subspinipes mutilans, from China. Photo by Yasunori Koide.

As The Ring progresses, scenes from the tape are reflected in the life of Watts’ character. Towards the end, as she is shuffling through an old box, a large centipede emerges and startles her before racing off into the darkness, not to be seen again. This centipede was another scolopendrid, but not polymorpha. The color pattern wasn’t unique enough to make a positive identification. In other words, I was partially covering my eyes when the centipede emerged.

Scolopendra heros. Photo by Aaron Goodwin.

Scolopendra heros, another scolopendrid from North America’s deserts. Photo by Aaron Goodwin.

A lot of biologists get annoyed when their favorite animals are used in horror movies, especially when the movie either completely misrepresents the animal in question or is just really bad. But I have to say, I don’t really mind when giant centipedes are used to increase the scare factor of a scene, especially in a movie as good as The Ring. Frankly, the reasons people like to put them in movies are all the same reasons I find them worth studying. Centipedes are pretty scary, at least the giant ones. They’re the perfect combination of long, slithery snake-ness with many-legged, venom-injecting spider-ness. But they are also mysterious, fascinating, and awe-inspiring creatures, and the world would be a poorer place without them. They are beautiful nightmares.

Cited:

Molinari, J., E.E. Gutiérrez, A.A. De Ascenção, J.M. Nassar, A. Arends, R.J. Marquez. 2005. Predation by giant centipedes, Scolopendra gigantea, on three species of bats in a Venezuelan cave. Caribbean Journal of Science 41(2): 340-6.

Webber, M.M., and M.R. Graham. 2013. An Arizona bark scorpion (Centruroides sculpturatus) found consuming a venomous prey item nearly twice its length. Western North American Naturalist 73(4): 530-2.

Yang, S., Y. Xiao, D. Kang, J. Liu, Y. Li, E.A.B. Undheim, J.K. Klint, M. Rong, R. Lai, and G.F. King. 2013. Discovery of a selective Nav1.7 inhibitor from centipede venom with analgesic efficacy exceeding morphine in rodent pain models. Proceedings of the National Academy of Sciences 110(43): 17534-9.