The Lyons Share

Crestfallen

Posted by Graeme Lyons , Thursday, 23 February 2012 18:54

Whilst poking around in the bottom of a quarry this afternoon I found a Badger's skull. I see a lot of these now, perhaps even more than those of Fox. I am always impressed by the sagittal crest on a Badger's skull. This 'crest' is where the jaw muscles attach to and is only present on animals with incredibly strong jaw muscles. It's also meant to get larger on older animals according to one website. What is strange about this particular skull is that the crest is hardly developed at all. What's more, the skull is bigger than any other Badger skull I have seen.

Here is a more typical Badger's skull (with jaw attached).

And here are the two together.

So what is going on here? If the sagittal crest does grow with age, that suggests there may be an environmental response involved, i.e., maybe Badgers which chew a lot, get more of a work out and therefore get bigger crests? Maybe this Badger lived on nothing but earth worms and marsh mallows and didn't develop a crest? Well it sure got big on whatever it was eating. I'd be interested to hear what people think. I am going to eat nothing but toffee pennies from Quality Street now and see if I can develop my own sagittal crest. Watch this space.

And to rule out dog, which have very different hind molars, here are the only teeth present.

Posted in bones, Ditchling Beacon, mammals

7 Response to "Crestfallen"

Anonymous Says:

Sounds about right fella - bone does grow/mould itself inline with muscle development - I have seem similar ridge structures on other mammals and showing a variety
of ridge sizes within same species - so cranial crest would mirror muscle dev as a result of feeding behaviour/environment/food availability - gud call :)

23 February 2012 at 19:16

Rob Says:

More and more people feed badgers these days. Maybe this individual got regular servings of dog food or similar?

With regards to differences in crests/bony processes: I was at the Jorvik centre in York recently and they have a few skeletons on display there. One of them was presumably a young warrior with several nasty nicks on his bones. You could really see the much larger processes on his arms where his biceps attached, especially compared to the remains of the townsfolk also on display. I think they identify archers at battlefield digs in a similar manner.

24 February 2012 at 00:11

Chris Sydes Says:

Cubs start off without the interparietal ridge/sagittal crest, don't they? I have found full size skulls with no ridge before and assumed they were badgers who died, probably in their first winter. However with all the fierce play biting they do through their first summer (and beyond) you might think the ridge would develop more rapidly.

24 February 2012 at 14:47

Nyctalus Says:

Hi Graeme, Interesting. The age explanation is also given in an old edition of 'Mammals of Britain - their tracks trails and signs' by Lawrence and Brown which says 'the sagittal crest is well developed, especially in old mature animals'. Maybe it isn't a diet difference then - just that your second skull is of a young adult that hasn't had the time to develop the crest yet?
However, they do seem remarkably different...
Allan

24 February 2012 at 22:02

Charle Kilshaw Says:

I found a very similar full sized badger skull recently and it also perplexed me! No crest, and further the lower jaw was detached like yours, which is usually impossible to do so without breaking the jaw. I had wondered if this missing jaw may have been a result of badger baiting... but now I reckon the jaw and crest oddities must be connected, resulting in an unusually weak bite. The 'soft food' only hypothesis is very interesting! I had also wondered if this may have been the result of genetic mutation or inbreeding, a weak jawed runt! I showed my father, also an ecologist, and at first he refused to believe it was a badger due to the missing crest and jaw, but I found it from a definate badger carcass! Plus I've just checked the molars, thanks to your ID tip there. Cheers for this! What a coinkidink!

15 May 2012 at 12:33

Charlie Kilshaw Says:

Continued thoughts on this! - It doesn't make sense that the crest would be missing simply due to a soft food diet: muscle mass will build up with use, but the bone growth that the muscle attaches to cannot! Bone growth is determined genetically, it's either there or it isn't. It can't develop from a need to connect increased muscle mass! Also it has been shown that cubs lack the crest, so therefore the genes that allow/cause this growth are 'turned on' and expressed in adulthood due to a factor relating to time or some seasonal trigger. Therefore i beleive it is more likely this lack of crest, on these large adult skulls, along with reduced jaw size (allowing it's removal), is down to those genes not being triggered, or are themselves defective copies etc. A plausible cause of this may be due to increased isolation of populations, and therefore inbreeding. I'd be very interested to hear any further thoughts on this!! Cheers! Charlie

15 May 2012 at 16:34

Graeme Lyons Says:

Hi Charlie
Although I believe you could well be right about the genetic character traits, bone DOES change with increased use of the associated attached muscles. The shape of bones of human remians for example, is often used to show how muscular the owners were likely to have been. I do not believe it is likely to be the only part of this mystery, but we can't totally rule it out. Thanks for your comments by the way.
Graeme

15 May 2012 at 17:49