Tetrapod Zoology

My dead mole

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Phil Budd (of the Southampton Natural History Society) recently gave me a dead mole Talpa europaea, and here it is. It isn’t the first mole for my collection: I have another one that I skeletonised long ago. Moles really are amazing. Their forelimb and pectoral anatomy has to be seen to be believed, and is so modified relative to what’s typical for mammals that even some experienced people struggle to identify elements of the mole forelimb skeleton. The short-shafted humerus sports immense expansions and crests for hypertrophied musculature, the sternum is highly elongate and deeply keeled, and the massively broad hand includes a huge sickle-shaped sesamoid and gently curved, stout claws (Yalden 1966, Whidden 2000, Sánchez-Villagra et al. 2004)…

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Mole teeth are pretty neat too. The upper canine is particularly large and unusual in being double-rooted. In the lower jaw, the canine is so small that it looks pretty much the same as the three small incisors, but the first premolar is enlarged and caniniform [see skull below: from skullsite]. The molars have large pointed cusps where the crests on top of the teeth (the ectolophs) have a dilambdodont configuration: this is where the metacone and paracone form the lower ‘valleys’ of a W shape and the metastyle, mesostyle and parastyle form the three ‘peaks’ (the metacone and paracone are on the lingual side of the molar, and the metastyle, mesostyle and parastyle are on the labial side). Shrews and some bats are also dilambdodont. Talpa europaea is pretty small: head-body length is 11-15 cm, tail is 2-4 cm long. It’s one of about nine Talpa species; they occur from western Europe to Siberia, but the systematics of this group is controversial. Talpids – ‘true moles’ – also occur in North America, and they’re not all fossorial specialists. Some are more shrew-like and only semi-fossorial, and some (the desmans) are amphibious. I am resisting the urge to elaborate.

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Here in Britain there is a lot of conflict between people and moles. It seems that many people enjoy maintaining vast, flat, barren spaces covered by nothing but grass. Moles are good at screwing with this tidiness – Macdonald (1995) reported a field covered by 7380 molehills per hectare. This adds up to 64500 kg of displaced soil amounting to 40 cubic metres, or to 25 km of tunnels. Besides the aesthetic damage molehills do to golf courses and so on, molehills encourage weeds and can also contaminate silage with the bacterium Listerella. Apparently, King William of Orange died in 1702 after falling off his horse, and the horse had stumbled over a molehill. This ended William’s plans to subjugate the Scottish clans.

Moles are highly territorial and, mostly in June, juveniles disperse from their parental territories and end up getting into all kinds of japes and scrapes. They get eaten by raptors, cats and dogs, and end up dead on roads a lot. And I need to stop there, but there’s so much more to say. Oh well…

Refs – -

Macdonald, D. 1995. European Mammals: Evolution and Behaviour. HarperCollins, London

Sánchez-Villagra, M. R., Menke, P. R. & Geisler, J. H. 2004. Patterns of evolutionary transformation in the humerus of moles (Talpidae, Mammalia): a character analysis. Mammal Study 29, 163-170.

Whidden, H. P. 2000. Comparative myology of moles and the phylogeny of the Talpidae (Mammalia, Lipotyphla). American Museum Novitates 3294, 1-53.

Yalden, D. W. 1966. The anatomy of mole locomotion. Journal of Zoology 159, 55-64.

Comments

  1. #1 Mary Blanchard
    June 23, 2008

    You should learn to share when you have multiple skeletons, I don’t have a mole! Did pick up a rather large (and sadly headless) fish from the beach Friday, which stank so badly I didn’t ID it properly, although I do have photos somewhere.

  2. #2 luca
    June 23, 2008

    Nice post, any way ou could include pictures of all those features you’re describing?

    I have to admit I ran into trouble with some moles this winter, but tried to send them away in a rather peaceful way, with a noise-emitting machine bought from the local equivalent of B&Q. It took a while to work, though, and I think they were sent away by something else…

    I do keep my grass delightfully rich of weeds, though, (aka: biodiversity), and try to leave some parts unattended and overgrown so that frogs and other critters can share it with me…

  3. #3 Ian
    June 23, 2008

    You should probably have surgery on that mole. They can turn cancerous, you know….

  4. #4 Jerzy
    June 23, 2008

    Please, please, please,

    Do a review of Lipotyphla and other ex-Insectivora. Lots of fascinating stuff, like not-dead selenodon and armored shrew!

  5. #5 Jerzy
    June 23, 2008

    “Macdonald (1995) reported a field covered by 7380 molehills per hectare. ”

    Do I sense competition coming? Tetrapod Friendly Competition – find the meadow with most molehills on one acre! ;)

  6. #6 Mike from Ottawa
    June 23, 2008

    How interesting can a mole skeleton be. I’ll bet there’s not a trace of pneumaticity to it. :-)

  7. #7 Atila
    June 23, 2008

    Nothing is better than knowledge when it cames to explore things. I would never think in so many things looking to a dead mole, even being a biologist.

  8. #8 Craig York
    June 23, 2008

    I hate it when you resist the urge to elaborate…I learn so much less that day. Great post, anyway. The Mole skull
    looks like something designed by H.R. Geiger…

  9. #9 AnJaCo
    June 23, 2008

    Some neighbor kids once brought me a live Eastern Mole – Scalopus aquaticus – that they had saved from a cat. They brought it in a bucket. I picked it up to check it out, and hoo-boy those forelimbs are strong! It was impossible to restrain from ‘burrowing’ down between my fingers, so my holding him/her must have looked a bit like someone ‘holding’ a hot potato. “Hypertrophied musculature” in action.
    [The mole seemed alright and was released some distance from the cat.]

  10. #10 Darren Naish
    June 23, 2008

    Mary, the next dead mole I have is yours. Now there’s an offer you don’t get every day.

    Mole anecdotes: my friend Tara rescued a mole from the road and put it in a plastic bag. Trying to dig out of the corner of the bag, its forelimbs waving, it rotated rapidly like a corkscrew. We imagine that moles and other fossorial animals scoot along their tunnels on their bellies, but maybe sometimes they’re on their backs or sides.

  11. #11 Zach Miller
    June 23, 2008

    I love moles. Now here’s a question about them (or two):

    Golden moles: What the heck are they?

    I saw in that Dougal Dixon “World Encyclopedia” that there’s a fossil “mole” with no limbs and a sort of armored, spade-shaped noggin. What the heck is that?

  12. #12 Max Paddington
    June 23, 2008

    Zach Miller, I believe the creature you’re referring to was a type of hedgehog that adapted for burrowing. Unfortunately I completely forgot the name of it, and where I saw it discussed, but it was certainly a cool article.

  13. #13 Darren Naish
    June 23, 2008

    Woah Zach, that’s some heavy questions you got there…

    What are chrysochlorids? Current evidence would have it that they’re close relatives of tenrecs, the two forming a clade termed either Afrosoricida or Tenrecoidea, within Afrotheria. I shouldn’t say it I know, but I am hoping to cover them here soon.

    Re: the fossil ‘armoured mole’ in Dougal’s new encyclopedia.. why, it’s the Late Oligocene N. American hedgehog Proterix, which Emile blogged on fairly recently [alas, that link seems not to be working for me at the moment]. It’s been mentioned here before – I thought by you! I’m not entirely sure where the limblessness idea comes from however; it wasn’t mentioned by Gawne (1968) in her review of the taxon (she implied that the weird vertebrae of Proterix suggested a Scutisorex-style lifestyle), so is presumably pretty recent. Does anyone know?

    Having mentioned hero shrews, Cameron did some good stuff on them here.

    Ref – -

    Gawne, E. L. 1968. The genus Proterix (Insectivora, Erinaceidae) of the Upper Oligocene of North America. American Museum Novitates 2315, 1-26.

  14. #14 Zach Miller
    June 23, 2008

    Thanks for the info and the link, Darren (which works now). No, it wasn’t me that mentioned the little wierdo–Dixon’s tome was the first place I’d heard of it. And neither of them are actually moles, eh? Very interesting. Of course, Fruitafossor demonstrates that mammals will eagerly adapt to a burrowing lifestyle if given the chance.

  15. #15 John Scanlon, FCD
    June 23, 2008

    If anyone can point me to primary references for the limblessness hypothesis, I’d be much obliged. I just looked up Gawne ’68 on the AMNH free-download site, and the only vertebrae reported are identified as ?lumbars.
    I’m reminded of a specimen I saw on the website of a small local museum in the UK a couple of years back, which had been found in the wall cavity of an old building and identified as a strange ritual or playful artifact, composite of a rat skull and snake vertebral column. The vertebral column was articulated but missing ribs, limbs or girdles, but it was actually (obviously!) a mammal, presumably the same rat. If Proterix specimens preserved in burrows underwent a similar partial disarticulation, that might explain the observations. Otherwise, it would be the only example of complete limb loss in a mammal, and a pretty big deal. Extraordinary evidence, please!

  16. #16 Tengu
    June 24, 2008

    That was cool, I knew moles were pretty impressive, but as usual you tell us so much more.
    I have not seen a dead one, but several times found live ones on the surface, they have such cute velvet fur, but do be aware of their strong jaws and sharp teeth.
    Is it true they eat their weight in earthworms a day? though moles help rotate the soil, what does gobbling all those valuable wrigglers do to soil condition?

  17. #17 Mary Blanchard
    June 24, 2008

    Thank you!

  18. #18 Max Paddington
    June 24, 2008

    I’m suddenly reminded of the observations I made when I captured a live mole on the surface once. It didn’t bite, but it was incredibly hard to hold on to and it made some very angry squeaky-hissing noises at me.
    The interesting part was when I released it into some nearby grass, eager to observe its burrowing behavior. It ran about on the grass in that strange waddling gait that moles employ until it found a ‘suitable’ piece of ground. As it ran through the grass it left a ‘trail’ of scratched up and torn ground. It then seemed to shove its face into it and wrench with its claws… the soil actually made an audible ripping sound every time. As it dug the creature rotated on the spot in much the same ‘Corkscrewing’ fashion that Darren Naish described in an earlier comment.
    That’s about the limit of my ‘scientific’ observations on moles.
    One further thing, how fast can a mole actually dig? I can’t count the number of times I’ve dug up tunnel systems trying to find the animal at the end, with absolutely no luck. :(

  19. #19 Nathan Myers
    June 24, 2008

    The expression is, “If I had two dead moles, I’d give you one”. A Texan would say, “As long as I got a dead mole, you get half.” (Texans are more used to biscuits and armadillos in this context, but extrapolate easily from armadillos.)

  20. #20 Sandra Naish
    June 28, 2008

    You see Darren, I do read your blog intermittently to check what you’re up to! Thank you for an explanation of why years ago (when you were a lad) I found a dead, rather flattened, mole in the road in the middle of a city suburb.

    I always thought it strange that the unfortunate creature was surrounded by tarmac, but it must have been a juvenile from a nearby garden leaving the family home. I was amazed to see its huge front limbs – but didn’t bring it home, because in your boyhood any requests for dead things to study were ignored. Love Mum.

  21. #21 Graham King
    June 28, 2008

    the metacone and paracone are on the labial side of the molar, and the metastyle, mesostyle and parastyle are on the labial side

    ALL on the labial side? (I admit I don’t know any of these cone-style terms, Darren, but maybe something’s amiss here, not what you meant to say?)

    [from Darren: I screwed up, have now corrected. Thanks for pointing this out.]

    I love the weirdness of moles. Takes me back to 5th Year Biology and a book by Kenneth Mellanby, The Mole. No doubt you know it? More obscure, how about The Inrichment of the Weald of Kent, by Gervase Markham (1568-1636)? In it, reportedly you can capture moles by burying a brass basin or cauldron up to its rim in the soil and placing one mole in it, which -unable to climb up the smooth sides- will ‘presently begin to strike or complain or call’ thus summoning others, which will tumble in, and noisily summon others in turn…
    Has anyone tried this method within living memory, I wonder, and with what result?

    Much fine and obscure lore about moles and molecatching as a family trade here

    Looking at the mole-skull, I think it (like various odd skulls ancient and modern) could provide scope for a ‘Spot-the-(Eye)Ball’ competition. Or ‘Pin the Pupil on the Moley’. With an exOrbitant prize of course. (OK, it may be obvious to you where it goes…)

    Finally… Darren, have you shared, or will you share here please, your tips and experience of skeletonising and mounting skeletons? I’d like to learn how… is it compatible with domestic harmony? I have rabbits – 4 adults and 1 juvenile, a stoat, a grey squirrel, a pike, a frog and two passerines to deal with… all found dead by the wayside… and if I learn how, I’m sure a deer may come my way too…

    [from Darren: excellent idea, I will aim to blog about this subject at some stage.]

  22. #22 Chelydra
    July 1, 2008

    Don’t forget, it’s not just desmans- the star-nosed mole (Condylura) is also highly amphibious.

  23. #23 anthony holmes
    March 26, 2009

    Hello , at last I have found someone who might be able to answer my question .
    Evidently moles have very sensitive noses and whiskers . However what’s puzzling me is what do the moles do with their snouts when digging ? Their arms and hands do not appear to be long enough to place in front of their face , so the front of their face must be pressed up against the wall of earth the mole is digging through . Surely this should create a great deal of wear on the nose unless the nose is directly behind and sheltered by their digging hands – which aren’t long enough to provide this shelter . Really puzzling , has anyone ever filmed a mole actually digging so we can see how they protect their face from the dirt. Hope you can help , best wishes Anthony.

  24. #24 Kate
    May 14, 2010

    Such an insight into moles! I was really fasinated what moles teeth looked like and now i know! Thank you so much you’ve made my day!