Friday mystery object #304 answer

Last week I gave you this skull to have a go at identifying:

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The skull of specimen LDUCZ-Z144 from the Grant Museum of Zoology

I thought that some of you would find it a bit easy, but the most diagnostic features aren’t visible in the image and it’s a nice specimen, so I went with it.

There is a bit of similarity with the skull of a ruminant, as noted by palfreyman14141, while Gerard pointed out that it’s from Africa and James M. Bryan was the first to drop a solid clue pointing to the correct species. As jennifermccaire says, it’s the very first on the list (assuming the list is alphabetical) – an Aardvark Orycteropus afer (Pallas, 1766).

An Aardvark at Detroit Zoo by MontageMan, 2008

An Aardvark (or as I prefer to call it, a Tippy-toes McSnuffleface) at Detroit Zoo. Image by MontageMan, 2008

Picking up on palfreyman1414’s observation about it looking like a ruminant, Allen Hazen asked an interesting question about the teeth, because the diet of these bizarre looking animals almost entirely consists of ants and termites, and most other mammals with a similar diet (like Pangolins and Tamanduas) have no teeth at all.

Making the presence of teeth even more weird is the fact that Aardvark stomachs have a muscular pyloric region that grinds up food in a similar way to a bird’s gizzard, so they really don’t need teeth for the major component of their diet. To top it off, the teeth of Aardvarks are utterly unlike any other mammal teeth – they’re made of tubules of dentine (giving the Order the name ‘Tubulidentata’), with no enamel, no pulp-cavity and no root – so they keep on growing:

The weird teeth of the Aardvark, made up of tiny dentine tubules.

The weird teeth of the Aardvark, made up of tiny dentine tubules.

All of this suggests that their dentition is distinctly non-standard, so it probably isn’t just a vestigial feature inherited from a toothed ancestor – which reinforces the importance of the question ‘why do they have teeth?’

Bear with me.

A 60-80kg mammal living in hot and water-scarce regions of Africa, will struggle to get enough moisture from ants and termites to survive, even if they are nocturnal and sleeping in burrows during the hottest part of the day. So how do Aardvarks do it?

Cucumbers, that’s how.

There is actually a species of cucumber that has a symbiotic relationship with Aardvarks, and it’s unimaginatively, but descriptively, called the Aardvark Cucumber Cucumis humifructus Stent, 1927.

Aardvark cucumber. Image by B. Strohbach

Aardvark cucumber (not a golf ball). Image by B. Strohbach

These weird fruits develop deep underground and have a tough skin that keeps them viable for months. Outside they’re like a leather golfball, but inside they’re watery like the cucumbers you’d put in a Hendrick’s gin and tonic – and that’s where the Aardvarks get their moisture (the Cucumber, not the G&T).

Nothing but the Aardvark has a nose sensitive enough to detect the plant, or claws powerful enough to dig into the hard-baked earth to access the fruits (or possibly only an animal that mostly eats ants is desperate enough for some culinary excitement to go to all that effort for something that the rest of nature views as a lacklustre garnish). The Cucumber’s seeds need to pass through an Aardvark to become viable and those seeds get distributed underground with a healthy dollop of fertiliser in what is otherwise a harsh environment.

The leathery skin of the Cucumber is almost certainly the reason why Aardvarks are alone in having teeth amongst the termite and ant-eating mammals. It also explains why those teeth grow constantly – and why they get so worn down.

I think that’s pretty awesome.

Now you may be wondering if I’m making all this up, but honestly, the world really is that weird (and wonderful) when you look at it closely enough!

Friday mystery object #304

This week I was worried that I didn’t have a mystery object planned, but then I stumbled across this on my phone:

mystery304

 

It’s probably a bit too easy for some of you, so I’d encourage using some cryptic clues and hints to say what it is in the comments box below.

I’ve had a problem with spam comments recently and have switched on a filter to ensure that people’s first posts are approved (regular posters shouldn’t be affected) – fear not, I will be keeping an eye on it and approving first timers!

Have fun!

Friday mystery object #302 answer

Last week I gave you this egg to try your hand at identifying:

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Eggs can be tricky, since they are largely similar in shape and, since egg collecting was banned many years ago, there are few modern resources for identification.

However, you can pick up clues by thinking about colour and pattern and working out what advantage it may have. So you might expect a brightly coloured egg to be laid in a well disguised and deep nest, where it’s unlikely to be spotted except by the parent, whereas a yellowy speckled egg is more likely to be camouflaged if laid in a fairly open, sandy environment.

So this egg was probably laid somewhere near the sea, which means it’s probably from a charadriiform bird (those are the shorebirds).

Now there are a lot of shorebirds, but this egg is pretty big and it lacks the strongly conical shape you’d expect from a cliff-nester like a Guillemot (the shape means it rolls in tight circle, making it less likely to be blown or knocked off a cliff). That actually narrows it down to a handful of birds that makes comparison easier. Curlew eggs, for example, are a similar size, but they tend to be more grey and have larger blotches, plus they’re a bit less elongated.

This particular egg has the shape and colour of a gull egg and large size means it’s almost certainly the egg of a Greater Black-backed Gull Larus marinus Linnaeus, 1758.

I would say more, but at the moment I’m at the natural history highlight of the year – the NatSCA conference. Here’s the Twitter feed in case you’re interested in the discussion:

Friday mystery object #301 answer

Last week I gave you this mystery tooth to have a go at identifying:

mystery301bmystery301a

There were a variety of answers, but the first few took this as a worn canine tooth, presumably due to the respectable size and robustness. However, consensus shifted to this being an incisor, meaning it would have to be from a large animal – which is spot on. Moreover, it’s a large animal that was once resident in Ireland.

After that there were a variety of ideas brought up, from all manner of beasts including Sheep, Badger (or perhaps Pine Marten since a cryptic M.m. from the Irish fauna could be either Meles meles or Martes martes), Cave Bear, Coyote, Wolf and even Human. There was one just correct identification however, by Tony Morgan who recognised it as a Hyaena incisor.

It is in fact the lower left third incisor (or i3) of Crocuta crocuta (Erxleben, 1777) – the tooth you can see in this (very gnarly) Hyaena mandible, although it’s much less worn:

Hyena mandible

Hyaenas have an incredibly thick enamel layer on their teeth which creates a distinct neck on the incisor where it stops, which is further defined by the root of the tooth bulging laterally below – presumably to help deal with the forces of prey capture and perhaps the Hyaena’s impressive bite strength.

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The robust skull of a specialist bone-crusher

You probably don’t think of Hyaenas as being native to Ireland, but until 39,000 or so years ago they ranged right across Eurasia, including those parts of Europe which were to be cut off by changing sea levels to form Ireland and Britain.

It’s strange to imagine a species normally associated with the African savanna strolling around the Emerald Isle, but it’s worth remembering that the world is a constantly changing place and wildlife moves around to cope as the environment alters. Borders and boundaries are very human concepts and other species only pay attention when you have a genuine barrier, like an ocean, a mountain range or (if you’re a Dormouse) a break in the tree canopy.

That’s one of the problems with current climate change compared to past climate variations. The speed of change is so great that some species don’t have time to move into new habitats and there are fewer suitable habitats available, because humans have cleared them for farming or building. Meanwhile, some other species can find suitable habitats and are able to move – but they will then often be considered an invasive pest. Now  the chances of Hyaenas returning to Ireland are pretty slim, but if they did I expect most people wouldn’t be too pleased, although you never know…

Kevin Richardson kisses hyena. Image by Kevin Richardson, 2007

Kevin Richardson kisses hyena. Image by Kevin Richardson, 2007

Friday mystery object #300 answer

Last Friday I gave you this new acquisition to have a go at identifying:

mystery300

When it arrived on my desk in an decorative box, with bundles of bone wrapped in blue tissue and tied with gold ribbon, it had a small label saying:

Skeleton of Mongoose, Africa.

Now, I know that having the continent would have been of help for the identification, but I didn’t want my 300th challenge to be too easy.

So how was that initial identification of Mongoose? It was certainly up there in the first of the comments, with Ric Morris (expert on British mammal bones, whose book I am eagerly awaiting) providing a beautifully crafted suggestion. Unfortunately it isn’t right, as the mongooses mongeese Herpestidae* tend to have a better developed post-orbital process (that’s the pointy bit on top of the skull, behind where the eye would be) and a corresponding process on the zygomatic (that’s the cheekbone), with the two sometimes meeting to form a post-orbital bar. They also tend to have more robust teeth.

Another (very) cryptic clue came from jennifermacaire who suggested that it was a civet (which can either be a type of viverrid carnivore or a French game stew). This suggestion was supported by henstridgesj and it’s closer than the mongoose suggestion, as the specimen is indeed from a species in the Viverridae. This was noticed by herpderpatologist who provided a handy tip for spotting the difference between mustelids and viverrids:

The split auditory bulla is a clue! It’s something I associate with viverridae;…

If we know that this is a viverrid, it narrows it down to one of  just 38 species…  which is still quite a lot. But by trawling through the images of viverrid specimens on the University of Michigan Animal Diversity Web it becomes easier to start narrowing down the likely group within the Family.

In this case it led me to the genets.

There are quite a few genets, with the Subfamily Genettinae containing in the region of 16 species. Distinguishing between them isn’t entirely simple, as they all look pretty much alike, but there is an excellent French resource that has detailed anatomical characters and images of specimens to help distinguish between genet species.

Working through this I found that the two best options were the Common Genet and the Cape Genet and distinguishing between them is not simple. I’m leaning toward the Cape Genet (or Large-spotted Genet) Genetta tigrina (Schreber, 1776), based on the spacing between the tympanic bullae (the bulbous bones under the skull that house the ear bones), the reduced lingual cusp on the P3 (that’s the tiny bit that sticks out towards where the tongue would be on the upper third premolar) the form of the upper first premolar (P1) and the shape of the maxillary-palatine suture (that’s the junction between the bone of the palate and the part of the upper jaw that supports all the teeth except the incisors).

That’s quite a lot to take in, but by getting your eye in and scanning through images it’s surprising how quickly you can narrow down options by rejecting images where you can see clear differences in the tympanic bulla configuration or cusp pattern on the P3 to leave a couple that need more careful consideration.

And just for the sheer squee of it, here’s what a Genet looks like when it’s alive:

Common Genet, by Peter 2011

Common Genet, by Peter 2011

I hope you enjoyed the challenge of the 300th mystery object!

 

*N.B. the plural of mongoose is “mongooses”.