Hainault Forest Website

Written and Designed by Brian Ecott

BE A NATURE DETECTIVE

Mammal Skulls

The Common shrew skull (left) is pointed and the teeth in the skull and lower jaws are red tipped. Skull length 2 cms. Skull and lower jaw of Field vole (middle) showing zigzag teeth pattern, length 2.2 cm. Skull of House mouse (right), length 2.2cms., showing enamelled teeth. The front molar has three roots compared to four in the Woodmouse.

Tooth pattern of Bank vole. Voles have three teeth on each upper jaw. The teeth edges of the Bank vole are rounded and the inner middle tooth has two lobes. The Field vole (centre) has teeth which are more sharply zigzag and the middle tooth has three lobes. The skull of a Woodmouse (right). By removing the first tooth four roots are clearly seen. The House mouse has three roots and the Harvest mouse has five roots.

Until decimalization the sixpence was a useful measure of shrews lower jaws. The pygmy shrew's jaw measures exactly half a sixpence, or 9.5mm. The common shrew's jaw was about two thirds diameter HEDGEHOG (above) and MOLE (below) together with Shrews are collectively known as Insectivores, but unlike the Common and Pigmy shrews the Hedgehog and Mole do not have the red tipped teeth. Their respective sizes of skulls are 6cm and 4cm.

The WATER VOLE has a similar teeth patterns and skull shape as other voles but is much larger. The 20p coin has a diameter 21.4 mm and the skull is twice this size.

Pelvis bones of Mouse and Vole showing the femur socket.

Top: Pelvis bones of vole.  The thin pubis (1) and concave posterior margin (2) indicate a female. Below: Pelvis bones of mouse. The short thick pubis (1) and rounded posterior margin with an angled point at tip indicates a male. Figure 3 indicated the hip joint socket.

CAN YOU FIND?

Look at the picture on the right of bones dissected from an owl pellet.

● Can you find a large skull at the top of the picture - is it a Mouse or Vole?

● Can you find a lower jaw bone belonging to this large skull?

● Can you find lower jaw bones of shrews? There are 6 there.

● Can you find any pelvic bones?

 

Small discarded pop bottle left in the Forest which has an entrance big enough for common shrews to enter but not get out. The contents show skulls, jawbones & pelvis.

RABBIT skull and lower jaws. Like field voles the teeth are grinding teeth to deal with the grass diet. Size up to 8.5 cm.

BADGER skull showing prominent zygomatic arch (Cheek bone) The skull length is 14cms.

BADGER Meles meles. This skull (left) found in the forest on Cabin Plain has a large sagittal crest on the top of the head denoting an old animal. Note how the lower jaw bone is jointed under the cheek bone  and (centre) Note the prominent sagittal crest denoting a very old badger.Front view (right) of badger skull,
Fox skull complete showing the large prominent canine teeth. Skull 15 cms. Fox skull found near Sheepwater. Good view of the molars and canines. The incisor teeth are at the front.

Recommended reading: Mammals of Britain - their tracks, trails and signs (1973) by M J Lawrence & R W Brown (Pub. Blandford) 

Tracks and Signs of Birds of Britain and Europe (2003) by R W Brown, J Ferguson, M J Lawrence and D Lees (Pub. Christopher Helm)