On Friday I gave you this object to identify:

It didn’t prove to be all that difficult, perhaps since the skull is distinctive in having the general appearance of a ruminant (in particular it is missing the upper incisors), but it also has canines and is very small, with a skull height of just over 5cm. This slightly unusual mixture of characters suggests one of the more primitive ruminants.

Jake suggested it might be a Muntjac or Chinese Water Deer, but as Lena pointed out, Muntjac (and Chinese Water Deer) have a scent gland in front of the eye (called a preorbital gland) that is housed in a big pocket in the skull.  The skull itself is also a bit small even for a Muntjac.

Jack Ashby, Lena, Barbara Powell and Jamie Revell all managed to work out that this skull was from a member of the family Tragulidae. To be more specific it is from a Greater Mouse-deer Tragulus napu (F. Cuvier, 1822).

These strange little ungulates are not really deer, despite their name. Both males and females lack antlers and the males have enlarged canine teeth used for display and to fight for mates – this specimen is from a female, as indicated by the small canines. Chinese Water Deer have a similar arrangement, but they have the preorbital gland and other specialised features that mean they are classified as true deer in the family Cervidae.

The Mouse-deer mainly live in Asia and this is the larger of two species that were considered one species until recently. The smaller of the two, the Lesser Mouse-deer,  happens to be the smallest species of ruminant in the world.  The Mouse-deer do have one African relative, the remarkable Water Chevrotain.

This small group of tiny ungulates live in tropical forests, particularly in wet and marshy areas, where they feed on leaves, flowers and other vegetation. They are themselves a handy meal for all sorts of birds of prey and carnivorous mammals, so it is perhaps unsurprising that they are secretive and have incredibly large eyes that help them spot danger. The troubles you face when you’re the perfect size for a snack.