Specialized Headgear

1. Specialized Headgear Antlers and Horns

2. Public Demand • The demand for antlers and horns of many different animals has fueled illegal hunting and trafficking • Rhino horns: used for dagger handles in the middle east, ground into powder it is used to treat fevers in traditional Chinese medicine • Elk antlers: Sold as an aphrodisiac (sometimes $200 per ounce) • Become a problem in America’s national parks

3. What does the forensic scientist need to know? • Forensic scientists are often sent parts from police seizures • First must identify from which animal the antler/horn came • Must be able to tell the season the antler was taken • Ex: Federal law says antlers in velvet must be treated w/ formaldehyde • Chemical tests can be run

4. Anatomy of Horns • Horns are a permanent part of the animals skull and have 3 layers • Both males and females have horns (female usually smaller • Horns are not shed • Except American Pronghorns, who shed the keratin sheath once a year

5. Anatomy of Horns • Inner layer: extends up from the skull as a bony core • Middle layer: called the sheath, it is a thin layer of blood-vessel-rich tissue that supplies blood to the outer layer • The sheath continues to grow throughout the animal’s life • Outer layer: called the keratin layer, it is the “horn” as we know it • Keratin is a protein that is also found in fingernails and hair

6. Anatomy of Antlers • Antlers grow from the skull and are shed once each year • Made of bone that grows from two disc shaped bumps on the skull (Pedicles)

7. Anatomy of Antlers • During the months when the antler is growing, the soft cartilage is covered by blood-vessel-rich skin called velvet • When the antler is finished growing, this tissue dies, the cartilage hardens to bone, and the velvet falls off • In all but one species (Caribou), only males grow antlers

8. How big do antlers and horns grow? • The size of a male’s antlers or horns tell a story • To grow large antlers, a male must be well fed and healthy • Has to carry the weight • Elk antlers can weigh up to 25-40 lbs. • Bighorn sheep horns can weigh as much as 30 lbs. • So what’s the purpose? • Rutting (mating) season is the one time males gather with female herds • Males battle with their headgear for territory and mates

9. Antlers Through the Seasons

10. Spring to Mid-Summer • Spring signals the start of new antlers • Soft layers of cartilage grow from pedicles • Grow very rapidly • Ex: moose antlers can grow 1 inch per day • But why? • An increase in daylight triggers the body to make high levels of the male hormone testosterone • This hormone stimulates antler growth

12. Late Summer • Antlers begin to harden into bone • Velvet begins to fall off • Males can be seen rubbing their antlers on trees to shed the velvet • But why? • Blood stops flowing through the velvet, causing the living tissue to die

14. Early Fall • Antlers are cleaned of all velvet • Marked with grooves and ridges where the blood vessels used to be • Remain firmly attached to the skull • This is the season of rut (mating) • Use their antlers to battle for territory closest to females • But why? • Testosterone remains high • Keeps antlers in place, but also affects behavior

16. Late Fall to Winter • Rut and mating season ends • Males go off on their own • Antlers fall off • Males can be seen rubbing partly attached antlers on trees to help things along • Can lose one antler at a time • But why? • Testosterone levels drop dramatically • Antler is no longer held to pedicle