Teeth Tell All

1. Teeth Tell All • Animal skulls provide info to scientists • Can identify a species • Many others: • Eating habits • Size • Gender • Brain development • Health • Cause of death • *Sometimes run a DNA test

2. What do forensic scientists need to know? • Parts of the skull • Differences between species • Use dichotomous keys and other resources • Look for distinguishing characteristics

3. How can a skull be identified? • Clues • Types, shapes, and patterns of teeth • Quickest clues • Other characteristics • Shape (round vs. oblong) • Size and position of eyes sockets and nasal passage • Shape of ear tube • Size of brain case • Distinct suture patterns

4. Types of Teeth • Incisors • Located across front of mouth • Used for cutting • Canines • Behind each side of incisors • Four at the most • Work like daggers • Used to grab and hold prey • Clues to food source can be found by presence or length

5. Types of Teeth • Molars and premolars • Cheek teeth that are located behind the canines • Wide teeth used for grinding, crushing, or cutting

6. Herbivores • Plant eating animals • Examples • Deer, Elk, Sheep, Cattle • Wavy-topped cheek teeth (molars and premolars) • Used to grind apart tough plant parts • Alternates between hard white enamel and softer dentine • Most herbivores do not have canines • Exceptions: male horses, pig family w/ tusks

7. Gnawing Herbivores • Examples • Prairie dogs, beavers, squirrels, rabbits • Have specialized long, curved incisors • Crack nuts, rip tough plants, chew through wood • These teeth are quickly worn down • Must grow continually through the animal’s lifetime • Incisors must stay sharp • Enamel! Outer face has an extra layer • Inner face covered in dentine • Other teeth are like typical herbivores

8. Carnivores • Meat eaters • Examples • Cat family, wolves, mink, badgers • Teeth are completely sealed and protected by enamel • Have long pointed canines to grab and hold prey • Sharp-edged incisors to cut through muscle • Cheek teeth vary in size and shape • Most resemble a cluster of tiny canines • Best for crushing and cutting prey

9. Omnivores • Eat both animal and plant material • Examples • Foxes, coyotes, raccoons, bears • Teeth are a mix between herbivore and carnivore • Canines not as sharp • Cheek teeth not as flat as herbivore • All teeth sealed with enamel

10. Insectivores • Eat insects • Examples: • Bats, shrews • Look like they have a mouth full of canines • All teeth are small sharp daggers • Sealed with enamel • Catch and crush hard shelled insects or arthropods

11. Trace Fossils Environmental Science Animal Forensics Unit

12. Trace Fossils • Temporary animal signs (anything that only lasts a short time, but is a clue the animal was there • Footprints • Blood trail • Nests • Scat/spoor/droppings • Cut vegetation • Burrows • Fur left behind • Scratches on trees

13. Trace Fossils • What is a track? • Usually refers to a footprint • Can also be a mark left on the ground from: • Tail, wing, hand, snake slither, etc. • People leave other unique tracks • Tire tracks, skis, snowmobile, etc.

14. Trace Fossils • Why are tracks important? • Can help scientists follow a suspect or victim • Animal prints can tell give us a lot of information: • Species • Age • Gender • Direction • Time of day • A series of tracks shows even more: • Speed, health, behavior

15. Trace Fossils • Not all fossils are equal • If DNA is present • Points to an individual • If there is no DNA • Can still point to a group • Narrow down list of suspects