Emma Sherlock is never happier than when she is out in the field, digging up worms © Trustees of the Natural History Museum

This month, in our series of the planet’s coolest jobs, we talk to Emma Sherlock, Senior Curator of Free-living worms and Porifera at the Natural History Museum. Emma spends her working life studying these wriggly creatures, researching how they build underground homes, create subterranean ecosystems and make it possible for all kinds of other species to exist. Keen to find out just how important the humble earthworm is? Let’s dig a little deeper…

What exactly is a ‘free-living’ worm?

The two main types of worms we work with here at the museum are free-living and parasitic. I look after the free-living nematodes (roundworms) and the annelids (segmented worms), which include earthworms, leeches and marine worms. I also look after the lineus longissimus (bootlace worms) – some of them can reach up to 50m!

What’s the coolest thing about your job?

Going to places where earthworm kingdoms are unexplored! It’s a bit like going back in time and experiencing a fraction of what people like Charles Darwin experienced. I often go to primary forests and countries with high biodiversity to find new species. A nameless species can’t be conserved or protected, so by putting a name to a new species you’re helping the whole conservation effort – in that respect you’re really making a difference.

Tell us a little about your typical work day

My days are varied – I never know what’s going to appear. Sometimes my colleagues will come back from Antarctica and other incredible places with a host of amazing new discoveries. I have a library of ‘pickled things’ – I look at the new specimens, find out their cool stories, and then get them all into my pickled library. I chat to worm researchers all over the world, and do my own research. At least once a day I set up my microscope, do a bit of distance counting and look at segment numbers between structures to try and discover something new. I’m working on a paper at the moment that shows how two species that were lumped together are definitely different. After a lot of measuring, I’ve found a very small characteristic that separates them.

© Trustees of the Natural History Museum

How did you become an earthworm expert?

As a kid I was part of my local natural history society – I loved butterflies and bugs and digging up worms to look at them. At university I studied zoology and then got a summer job working at the Natural History Museum. At the end of the summer they offered me a role in the specialist natural history bookshop, and while I was there I volunteered in the parasitic worm department, sifting through gorilla poo! Then a job came up in free-living worms, which I got. My first visitor in that role was Victor Pop, a man from Romania who had discovered some of the largest earthworm species in Europe. He was really inspirational and I went out to his lab in Romania, trained there and never looked back.

You recently went on a worm hunt to Nicaragua – tell us about that

A volunteering company were doing some conservation work there and could see that there were a lot of earthworm species, but absolutely none had been registered. So I went out to investigate. We sampled a load of areas and habitats and got 80 new species records for the country, and two new species for science in general.

How important are earthworms? What can they teach us about the earth itself?

They’re incredibly important! They are ecosystem engineers, working together as a unit with different jobs: breaking up the soil, aerating it to allow oxygen down, diminishing the effects of flooding with their burrows, breaking down all the dead organic matter on the surface and bringing nutrients back into the soil. If you go to an area where there are no earthworms, you know there’s something wrong with that soil.

You are the president of the Earthworm Society of Britain – what does that involve?

A lot of trying to enthuse people about earthworms. What we’re really after is getting biological recorders up and down the country to start recording earthworms, because one big problem we have is that there’s no baseline data, even for the UK. We just don’t know where the species are or which are the rare ones. There was one species we hadn’t seen for 32 years, but then we saw it again recently because we were all out there looking for earthworms and recording them. If we get more data we can tell if habitat destruction is a problem, or how climate change will affect the earthworms. If anyone wants to get involved come on our courses, get trained up and be a county recorder. Quite often there’ll be grid squares with no earthworms recorded at all, so it’s very easy to record ‘firsts’, which can be really satisfying.

What is your best piece of advice for someone who’d love to pursue a career like yours?

Probably two things. Firstly, it really helps to get a good degree, which involves working hard. The other thing is volunteering. Pretty much all the curators at the museum have volunteered at some point before – you gain a lot of experience through volunteering, and people in the field can get to know you. You can volunteer at most museums, sometimes in zoos and wildlife parks, and, of course, help us out at the Earthworm Society.

Excited about earthworms? Learn more about their habitat and underground world with our new title The Big Earth Book.