With six years of phd work on theropod dinosaurs behind him, Darren Naish mostly spends long hours in the library, hunched over his laptop. But he gets out sometimes, and picks up litter and pursues exotic lizards across the British countryside, aiming all the while to publish his technical work on obscure Cretaceous dinosaurs. He also messes around with pterosaurs, swimming giraffes, British big cats and stuff like that. He has given up on the stupid idea of being a dedicated academic and ekes out a living as a technical consultant, editor and author. He can be contacted intermittently at eotyrannus (at) gmail dot com. For more biographical info go 
The Natterjack Epidalea calamita (introduced in the previous article) is a remarkable animal, well adapted for the dry, relatively saline environments it inhabits (there are places where Natterjacks inhabit saltmarshes, moors, and disused industrial areas). A proficient burrower, it starts digging a burrow with its forelimbs but does most of the work with its hindlimbs (hindlimb burrowing is typical for anurans, whereas forelimb burrowing is highly unusual). The burrows help the toads to gain access to moisture in dry habitats because they typically extend down to damp sediments; a particularly absorbent patch of granular skin on the animal's belly enables it to make the most of damp sediments when they're encountered [adjacent photo by kind courtesy of Neil Phillips].
The Natterjack runs rather than hops, and runs around at night in rapid pursuit of ants, moths and other arthropods. During this nocturnal foraging, some individuals range far and wide (for their size), but others are far more sedentary: foraging ranges might be as small as 50 square metres, or might be 20 or more times this size. Some individuals are highly site-specific and show remarkable homing instincts. Beebee & Griffiths (2000) report that individuals transported 500 metres away from their home burrow 'into areas they have never seen before have been found back in their original burrow within a fortnight' (p. 106). It's still not known exactly how the toads are able to navigate so successfully [adjacent image shows Natterjack pair in amplexus, from wikipedia].
In Britain, the Natterjack is most common on the Irish Sea coast between Merseyside and the Solway Firth, and in the coastal areas of Norfolk and Lincolnshire. The species has declined catastrophically across the country and is now locally extinct across most of its range, mostly due to habitat loss. Its isolated presence in southwest Ireland has resulted in a lot of speculation - it's even been suggested that it might have been introduced, either by humans or by birds (how the hell is that supposed to work?) - but the commonest idea has been that it's a member of a relict Lusitanian fauna that evidences former links with Portugal. Rowe et al. (2006) showed that there was no genetic evidence specifically linking Irish natterjacks from those of the Iberian Peninsula, and that the Irish population had not persisted through times of Pleistocene glacial maxima: instead, it must represent an expansion from a north European clade that occurred more recently than 10,000 years ago (more recent than the coldest phases of the Late Pleistocene, but pre-dating the formation of the English Channel). The surprising discovery of a large Irish Natterjack population in the late 1960s (on the north side of the Dingle Peninsula) raised new suspicions of human translocation efforts, but recent work on genetic variation in Irish Natterjacks supports the view that this is actually a native, in-situ population (May & Beebee 2009) [adjacent picture of German Natterjack by Christian Fischer, from wikipedia].
Outside of the UK, the species occurs widely across Europe, being found in 21 countries across western, northern and east-central Europe. The Iberian Peninsula might be regarded as its stronghold; it is rarer and more sparsely distributed around the fringes of its range (the British Isles, Sweden and the Baltic states). It's absent from Italy and the Balkans. There are no recognised subspecies.
With the European common toad and Natterjack out of the way, I'm going to stick with the theme of looking at 'familiar' Northern Hemisphere species in the next article. After that, things get increasingly obscure...
- Toadtastic - the invasion begins!
- Bidder's organ and the holy quest for synapomorphies
- Our sex lives in words and pictures (or, On the reproductive biology of the Bufonidae)
- Skulls, crests, snouts and giant poison glands: the heads of toads
- Toads of the world: first, (some) toads of the north
For previous articles on hyloid anurans see...
- Britain's lost tree frogs: sigh, not another 'neglected native'
- Ghost frogs, hyloids, arcifery.. what more could you want?
- Green-boned glass frogs, monkey frogs, toothless toads
- It's the Helmeted water toad!
- Horn-headed biting frogs and pouches and false teeth
- More wide-mouthed South American horned frogs
- We need MORE FROGS
Refs - -
Beebee, T. & Griffiths, R. 2000. Amphibians and Reptiles. HarperCollins, London.
May, S. & Beebee, T. J. C. 2009. Recent introduction or ancient ancestry? Use of genetic evidence to investigate the origins of range edge populations in natterjack toads (Bufo calamita). Conservation Genetics doi: 10.1007/s10592-009-9805-4.
Rowe, G., Harris, D. J. & Beebee, T. J. C. 2006. Lusitania revisited: a phylogeographic analysis of the natterjack toad Bufo calamita across its entire biogeographic range. Molecular Phylogenetics and Evolution 39, 335-346.
Comments
Same way as always: by eggs sticking to feathers of waterbirds.
Given the distances involved, however, that ought to lead to desiccation and death, I suppose.
Posted by: David Marjanović | October 28, 2009 7:09 AM
Yeah, as you surmise, epizoochory just cannot work for toads: their eggs can survive out of water for, at most, a few hours, and even this would be exceptional.
Posted by: Darren Naish | October 28, 2009 7:13 AM
The natterjack is a bit more wide-ranging than that, actually. It's found as far north as southern Sweden and Estonia, respectively, and as far east as Belarus.
Posted by: Dartian | October 28, 2009 7:34 AM
Thanks, I'll correct.
Posted by: Darren Naish | October 28, 2009 7:37 AM
The natterjack's distribution is actually quite interesting. It seems* that certain mountain chains such as the Alps, and possibly the Carpathians, have been unsurmountable biogeographical barriers to its dispersal. And yet the natterjack has succeeded in bypassing the Pyrenees (in whichever direction). It would be interesting to know if there are other European anurans, or other microvertebrates, that show a similar distribution pattern.
* 'Seems' being the operative word.
Posted by: Dartian | October 28, 2009 8:02 AM
insurmountable. *Sigh!*
Posted by: Dartian | October 28, 2009 8:08 AM
I can't wait until you get to the North American toads.
Where I live there are two similar species--the Americantoad and the Fowler's toads--and they are very hard to tell apart.
They also hybridize.
In fact, American toads, Fowler's toads, Woodhouse's toad, and the Southern toad have all been known to hybridize where the ranges of two species overlap.
Posted by: retrieverman | October 28, 2009 8:46 AM
An interesting series of articles. I have some photos of Bufo borealis at my site - found in the Alberta Rockies, a juvenile with orange toes.
Posted by: Adrian Thysse, FCD | October 28, 2009 10:14 AM
I used to dig for fossils in Miocene sands in SE Spain, beautiful Scutella and Clypeaster sea urchins. The area is dotted with salt lakes. Often deep down a hole, we'd come across a Natterjack. I was always surprised of how deep the dig their holes. Also, they are thought to have survived through glaciations in the Iberian Peninsula and migrated north through possible two routes E and W of the Pyrenees - coastal, most likely. Therefore their grographic distribution
Posted by: Blackbird | October 28, 2009 10:27 AM
Natterjack is a wonderful name, but I'm a lttle vague on
what it signifies-some relation to how it vocalizes?
I was also surprised that it runs rather than hops. I'd
never heard of this in frogs or toads before, and I gather
its fairly uncommon.
Posted by: Craig York | October 28, 2009 11:10 AM
Ah the humble little natterjack. I was dead chuffed when I finally saw one (even though it was captive) in the New Forest Reptile centre. I yet to see one in the wild.
I read an interesting paper on their conservation where they had dug out their breeding ponds to stop them drying out but these started to be used by other amphibians which out competed the poor natterjacks. It turns out the natterjacks need pools that are to difficult for others to survive in i.e those that dry out or become inundated by sea water for many of the years, removing the competion and in the few good years the natterjack numbers would be sustained by their large numbers of young.
Posted by: Neil | October 28, 2009 2:38 PM
Does anyone know the etymology behind the word "Natterjack"?
Is this a British English word? As far as I know, it doesn't exist in American English.
Posted by: retrieverman | October 28, 2009 3:09 PM
@ Craig York and retieverman;
“A natterjack” could well be a misdivision of “An atterjack” just as “A newt” is a corruption of “An ewte”. Cf “attercop” (poison-head), the old name for spider.
Posted by: pomposa | October 28, 2009 3:28 PM
Regarding Craig York's comment, the Boreal toad is also more inclined to walk rather than hop.
Posted by: Adrian Thysse, FCD | October 28, 2009 3:42 PM
On a birdwatching trip to Norfolk a few years ago I was amazed by the noise coming from the field behind the house where we were staying. Thinking it was from some bird we had yet to see I checked with a local naturalist. "Hell no, that's the Natterjacks".
The next evening there was one on the doorstep!
They ARE quite noisy.
Posted by: John Opie | October 28, 2009 5:27 PM
A little video of a Natterjack running:
http://www.youtube.com/watch?v=9DHpqYj4zDI
Posted by: Will Baird | October 28, 2009 9:29 PM
And another:
http://www.youtube.com/watch?v=9DHpqYj4zDI
How salt resistant are they, btw?
Posted by: Will Baird | October 28, 2009 9:31 PM
Will:
It varies. In Spain, natterjack salinity tolerance differs widely between different populations (the most tolerant will breed in brackish water*). And even the least tolerant Spanish natterjack populations have shown higher salinity tolerance than any British natterjack populations studied thus far (Gomez-Mestre & Tejedo, 2005).
* 'Brackish water' is, of course, a relatively broad concept as it covers a pretty wide range of salinity regimes (at least from a lissamphibian's point of view).
Reference:
Gomez-Mestre, I. & Tejedo, M. 2005. Adaptation or exaptation? An experimental test of hypotheses on the origin of salinity tolerance in Bufo calamita. Journal of Evolutionary Biology 18, 847-855.
Posted by: Dartian | October 29, 2009 3:34 AM
It seems that they also disperse by means of salad bags.
Posted by: windy | October 29, 2009 4:13 AM
Would that be a case of sainsburochory?
Posted by: Dartian | October 29, 2009 4:33 AM
Well, the species doesn't occur in America, so...
:-D :-D :-D
What about epiphytochory?
Posted by: David Marjanović | October 29, 2009 8:01 AM
The word 'Natterjack' is apparently derived from both 'naedre' (an Anglo-Saxon word meaning 'nether' or 'lower') and 'jager' meaning 'one who runs'. Adder is also apparently a corruption of naedre: it seems that the word was used widely for creatures that crawl or run around close to the ground. The loud calls of Natterjacks have inspired various local names such as Thursley thrush and Birkdale nightingale, and they're also called running toads and golden backs in parts of the UK. All info from Beebee & Griffiths (2000).
Posted by: Darren Naish | October 30, 2009 6:52 AM
For a better video of a running Natterjack, try this (though the toad runs out of steam about halfway through).
Posted by: Darren Naish | October 30, 2009 6:57 AM
Interesting. German Jäger = "hunter".
Lots of videos to watch for the weekend...
Posted by: David Marjanović | October 30, 2009 7:33 AM
Wow...I've seen Bufo boreas walk (a lot!), but when they really want to escape, they'll hop. I've never seen a toad run like that! Very cool.
Posted by: Sven DIMilo | October 30, 2009 12:39 PM
damn anaerobic glycolysis..
Posted by: Sven DIMilo | October 30, 2009 12:41 PM