Specialized Headgear Antlers and Horns

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Specialized Headgear

Antlers and Horns

Public Demand

The demand for antlers and horns of many different animals has fueled illegal hunting and trafficking

R

hino 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

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

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

A

merican Pronghorns, who shed the keratin sheath once a year

Anatomy of Horns

I

nner 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 itKeratin is a protein that is also found in fingernails and hair

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)

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

How big do antlers and horns

g

row?

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 herdsMales battle with their headgear for territory and mates

Antlers Through the Seasons

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

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

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

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