Mongoose in paradise

I spent the last week in St. Croix in the U.S. Virgin Islands. It looks like this:

It’s pretty nice. Some call it paradise. Coconut palms, mangoes in profusion, bananas and pineapples growing wild. Hermit crabs retreat into their shells as you walk and go tumbling off the path.

Just before I took the above photo, I saw a flash of brown racing across the beach. Later, I saw another skittering along a road, and another into some brush. Long, mahogany furry bodies. Upstanding ears, little noses.

Squirrels?

Not here.

Meet the Small Indian Mongoose (Urva auropunctata).

Originally from northern India, the mongoose is now resident on almost all Caribbean islands, as well as all the major Hawaiian islands. And to me, it was a reminder that the story of the cane toad (as told in my book, which you should definitely get from an indie bookseller if you can because Indie Bookstore Day was yesterday!) is not one that is exclusive to Australia.* Every place, it seems, has an origin story. And every place has an animal that’s a symbol of their hubris.

The furry, racing bodies of mongooses in the Caribbean are a legacy that goes with the many ruined sugar mills that dot the island of St Croix. The legacy is one of sugar, slavery, and hubris.

The sugar and the slavery

In the 18th and 19th centuries, the Caribbean was a land of plantations, many of them producing and refining sugar cane. Sugar cane into white sugar. Sugar cane into brown sugar, sugar cane into molasses, into rum (they still make the rum. They import the sugar. EDIT: I forgot! One of the rum companies makes it from breadfruit! They import that, too). That sugar was grown on the backs of enslaved people, brought from West Africa and subjected to a life of backbreaking labor, 5.5 days per week, with a generous 1.5 days off per week which they were allowed to use to grow their own garden plots to feed themselves. (Uprisings against this? You bet).

But of course, sugar cane was imported to those islands in the first place, and it wasn’t the only thing that was. Rats scurried off colonial boats as well. And sugar cane is delicious to pretty much everyone, including rats. When yields declined in the everyone knew who to blame. They had to get rid of the rats.

The solution?

Previous islands had introduced mongooses to hunt the rats, starting with Jamaica in 1870s. They seemed to have better sugar yields after that so clearly this must have worked (?). So mongooses spread across the Caribbean and hit St. Croix sometime between 1877 and 1879.** (Unless it was 1884? It was before 1900.)

There are two major problems with trying to use mongooses to control rats, however.

1. Rats are nocturnal. Mongooses…are not.

2. Rats will eat anything. So will mongooses.

So mongooses didn’t do much at all to help the rat issue. They did, however, start eating everything else. Their overall impact on the island fauna is a bit debated. They may not threaten EVERY species. But they certainly wreaked havoc on others. The St. Croix ground lizard now doesn’t live on St. Croix.

Most people, unfortunately, don’t care much about a tiny brown lizard (St. Croix has many, many, many lizards). But they do care about sea turtles. St. Croix is home to the breeding grounds of the hawksbill, green, and leatherback turtles. In fact, that first picture? One of the best breeding grounds left for the hawksbill and green turtles. Kayaking around St. Croix, if you haven’t paddled into a shallow bay or inlet and seen turtle heads rising gently from the water…well you weren’t looking.

Thanks for reading Team Trash: Where People and Wildlife Meet! This post is public so feel free to share it.

Humans love sea turtles. And so do mongooses! Sea turtle eggs are delicious!

You see the problem.

The mongooses alone probably wouldn’t eat the turtles to extinction. But the turtles face many threats, from accidentally eating our plastic bags to getting caught in our boat propellers, to losing their nesting habitat because we wanted a nice marina.

Right now, efforts involve trapping the mongoose, and helping hatching sea turtles get to the ocean to start their (very dangerous) young lives. Turns out that trapping mongooses is a tricky proposition.

The hubris

What struck me most about this story was how incredibly similar it was to the story of the cane toad. Both the cane toad and the mongoose were brought in because of sugar cane crops and the animals that love them.

But the most key similarity is the problem of picking the wrong species for your biocontrol. Biocontrol is when you have a species problem, and you bring in another species that eats it, to control your problem without poison or hunting (well, without human hunting, someone’s definitely still hunting).

And biocontrol can be wonderfully, fantastically effective, when done right. What is it to do it right? To make sure that the predator you introduce eats your target species—and that nothing else it can eat is available to it. It eats the target species, and ONLY THAT.

Mongooses and cane toads are both generalists. Cane toads will eat any insect that moves and some that don’t. Mongooses are famous for attacking snakes, and yes they are absolute snake menaces, but they also will eat rats, other small mammals, small birds, chicken eggs, turtle eggs, small lizards…look if it’s got protein, and even if it doesn’t, a mongoose will try it once.

This is the hubris—the overconfidence that humans have. We assumed we knew that mongooses ate rats, and we assumed that was all we needed to know. We assumed not just that we knew what a mongoose would and wouldn’t eat, but that it would somehow read our minds, eat the rats we hated. In our history and our present, we often take a tiny bit of knowledge, assume that’s all we need to know, and let it go.

In this case, the knowledge we let go was a small, hairy predator of voracious appetite. And now, we—and the sea turtles we love—live with the consequences.

References

• Berentsen, A.R., W.C. Pitt, and R.T. Sugihara. 2018. Ecology of the small Indian mongoose (Herpestes auropunctatus) in North America. pgs. 251-267. In: W.C. Pitt, J.C. Beasley, and G.W Witmer, editors. Ecology and Management of terrestrial vertebrate invasive species in the United States. CRC Press, Boca Raton, FL. 403 pp.

• Miller, M.L. Island Mongoose: Conservation Villain or Scapegoat? Or Both? Cool Green Science, The Nature Conservancy, 2015.

• Small Island Mongoose, Invasive Species Virgin Islands.

• Barrat, B. Mongooses wiped them out. Now Nicole Angeli wants the St. Croix ground lizard home again. Smithsonian Insider, 2017.

• Sea Turtle Conservation in the US Virgin Islands The Nature Conservancy, 2024.

• Sandy Point National Wildlife Refuge, US Fish and Wildlife Service.

Where have you been?

• I hope it’s reading this amazing piece on “hormbles chormbles” which I cannot stop laughing at.

• Crows can do geometry and they probably do it better than me.

• If you needed more reasons not to get ticks it would be that now another species can make you violently allergic to red meat. I’m not a red meat person but I sure as heck don’t want to be allergic to it.

• If you need a break from life, you can participate in the great historical debate, and help count how many penises are in the Bayeux tapestry. Why have the Roman Empire be your Roman Empire when it could be this?

• More and more scientists are losing their funding through arbitrary decisions that are nothing but power plays. They are losing funding they already competed to win. And this means that people—and animals—will die.

Where have I been?

Um, St. Croix.

• But also I wrote another piece for National Geographic, this time on the amazing fungal networks that join trees and act as transport, moving important goods to trees in exchange for food! And yes, they’re a bit like the fungus in The Last of Us, but like, without all the nefariousness.

• And if you’d like to see my take on the dire wolves that weren’t, The Wolves of Theseus, you can see it here:

*Interestingly, they TRIED introducing the mongoose to Australia and failed.

**There is no grin on my face quite like the grin that I get when I see that the page I’m reading for information has a FULL SCIENTIFIC REFERENCE LIST AT THE END. That’s what I want to see and lord knows most scientific magazines don’t even have it. Thank you Invasive species page for USVI.gov. Never change.