Teeth Tell All Animal skulls provide info to

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Teeth Tell All • Animal skulls provide info to scientists – Can identify a

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

What do forensic scientists need to know? • Parts of the skull • Differences

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

How can a skull be identified? • Clues – Types, shapes, and patterns of

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

Types of Teeth • Incisors – Located across front of mouth – Used for

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

Types of Teeth • Molars and premolars – Cheek teeth that are located behind

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

Herbivores • Plant eating animals • Examples – Deer, Elk, Sheep, Cattle • Wavy-topped

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

Gnawing Herbivores • Examples – Prairie dogs, beavers, squirrels, rabbits • Have specialized long,

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

Carnivores • Meat eaters • Examples – Cat family, wolves, mink, badgers • Teeth

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

Omnivores • Eat both animal and plant material • Examples – Foxes, coyotes, raccoons,

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

Insectivores • Eat insects • Examples: – Bats, shrews • Look like they have

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

Trace Fossils Environmental Science Animal Forensics Unit

Trace Fossils Environmental Science Animal Forensics Unit

Trace Fossils • Temporary animal signs (anything that only lasts a short time, but

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

Trace Fossils • What is a track? – Usually refers to a footprint –

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.

Trace Fossils • Why are tracks important? – Can help scientists follow a suspect

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

Trace Fossils • Not all fossils are equal – If DNA is present •

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