Carl Zim­mer pos­ted an inter­est­ing art­icle last night about his­tor­ical biogeo­graphy, and the clues we can get about con­tin­ental drift (amongst other things,) from the dis­tri­bu­tion of fauna. Gen­er­ally smal­ler, less mobile, and more envir­on­ment­ally picky creatures are the most use, since they don’t tend to get around by other means, and this piece writes about one that fits the bill; it’s a tiny har­vest­man (an ancient order of arach­nids). Unfor­tu­nately, because Carl’s used a col­lo­quial name to refer to it, a lot of con­fu­sion has ensued; look at the com­ments if you want a taste.

The prob­lem is that the term he used — “daddy longlegs” — is used col­lo­qui­ally to refer to three dif­fer­ent types of creatures in vari­ous parts of the world, and if the com­ments are any­thing to go by he has a lot of read­ers from places that use it dif­fer­ently to him. Speak­ing as a Brit, a daddy longlegs is a crane-​​fly, which (until I remembered that it can also refer to a har­vest­man,) was a little con­fus­ing; since crane-​​flies are not par­tic­u­larly small, or par­tic­u­larly choosy about their envir­on­ment, and they can fly so the point about them not not mov­ing around much under their own power is some­what lost, as well. It could have been worse, though; if I was someone who’d imme­di­ately thought of the daddy-​​longlegs spider, I might not have even real­ised some­thing was amiss, and just gone away from the art­icle with the wrong idea entirely; not a desir­able outcome.

Now, I’m not hav­ing a go at Carl here, he’s an excel­lent writer, and he does an awful lot to present com­plex sci­ence in a way the lay­man (includ­ing me) can under­stand — and be enthused by. And, in fact, he does give the taxo­nomic clas­si­fic­a­tion of the har­vest­man he’s talk­ing about, so the sci­en­tific­ally lit­er­ate won’t be misled. My point (inso­far as I can be said to have one) is that while using a col­lo­quial name like this might make the writ­ing, and there­fore the sci­ence, more access­ible, we should be extremely care­ful to bear in mind that while they might seem friendly, col­lo­qui­al­isms are also notori­ously ill-​​defined and prone to mis­in­ter­pret­a­tion. It would be a real shame if, in order to make sci­ence access­ible to the gen­eral pub­lic, we also had to make it use­less to them by sac­ri­fi­cing the very pre­ci­sion and clar­ity that makes it so powerful.

Edit: Zooil­lo­gix reports the same research, and also neg­lects to cla­rify what type of daddy longlegs the mite har­vest­man is related to.

Edit 2: Richard Dawkins and Bug Girl have also linked to Zimmer’s ori­ginal, restat­ing the ambigu­ous term without cla­ri­fic­a­tion. This is par­tic­u­larly care­less from Dawkins, who’s Brit­ish, and so, pre­sum­ably, thinks of daddy longlegs as crane-​​flies himself.

Edit 3: This is the last one, I swear. The com­ments on Zooil­lo­gix post have sort of made my point for me; the images in the New York Times ver­sion of Zimmer’s art­icle that Zooil­lo­gix link are not, in fact, of the Har­vest­man at all, they’re of the Daddy Longlegs Spider, which is a closer rel­at­ive than the crane fly, but still not close enough. When your lan­guage is ambigu­ous enough that the photo research­ers of your own pub­lic­a­tion are con­fused, there must be some­thing wrong.