How to ID small mammal skulls
You've found a skull, but how do you know which small mammal it belongs to? The detective process starts here...
Skulls can tell you a lot about an animal’s diet and lifestyle. Start the detective process with size. Vole, shrew and mouse skulls are the size of an adult thumbnail, those of rats and moles are half as long as an index finger, rabbit and squirrel skulls are the length of a thumb, and badger and fox skulls are the size of one or two clenched fists. Any bigger and you probably have a deer, sheep, cow or horse skull.
Next look at the teeth – carnivores have pointed teeth with no gaps; herbivores have ridged grinding surfaces on their teeth and a long, toothless gap between the cheek teeth and the front of the jaw.
Here are some common species and key features to look for when identifying their skulls:
Rabbit Look for: a compact, 50mm-long skull; big upper incisors with a long gap behind; parallel cheekbones; blunt, oval surfaces on the cheek teeth.
Mole Look for: a very elongated, 30mm-long skull; tiny incisors in both jaws with no gap behind; other teeth that are small, pointed and tightly packed.
Red fox Look for: an elongated, 8–11cm skull; long canines and pointed incisors; huge eye sockets with concave pits above them.
Bank vole Look for: a 20mm-long skull; big incisors with a gap behind; zigzag surfaces on cheek teeth; prominent eye sockets. Often found in carnivore droppings.
Top tips Clean skulls by leaving them outside under a flowerpot with a gap for beetles to crawl inside - the beetle's maggots will clean the skull naturally. The flowerpot will protect it from other animals. Whiten skulls with hydrogen peroxide diluted several times, not with bleach.