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Bighorn Sheep And the Mojave Desert By Brian
Kaebnick
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General Description

• Around 4 feet tall
• Can weigh up to 300 lbs.
• Has a set of horns about 20 inches across and can
  weigh 30 lbs.
• Short deer like hair
• Light tan in color with a white tail

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Why Are Sheep In The Desert?

• Bighorns origins go back to Asia
• Crossed land bridge 100,000 years ago into North
  America
• During the ice ages areas in Alaska and Southern
  California were only place inhabitable by bighorn
  sheep ancestors
• As ice ages went away bighorn sheep adapted to
  their changing environment

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Reasons For Numerous Species

• As ice ages left bighorn habitat became segmented
  as the climate became drier
• Bighorn habitat moved up in elevation
• Lead to separation of species

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The New Environment

• As climate got drier the bighorns habitat moved
  up in elevation
• Now the desert bighorn live mainly in the
  mountains
• Less water,vegetation, and tree cover
• Terrain more rocky and exposed
• The only constant aspect of environment is lack
  of snow

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Adaptations Of The Bighorn

• Hollow hair for insulation from heat and cold
• Desert bighorn sheep have a tan coat that blends
  in to the brown rocks that make up much of its
  habitat
• Developed a keen eyesight because of lack of
  vegetation cover

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• Double lobed foot with sharp edges allow bighorn
  sheep to climb on rocks and steep cliffs up to a
  70 degree angle
• The bighorns eyes also help in judging distances
  when jumping
• These two features combine allow the bighorn to
  escape from predators like mountain lions

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• 4 chamber stomach with a 9 stage digestive system
  for maximum nutrient absorption
• Able to get daily allowance of water from plants
  during winter months

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Food For The Bighorn Sheep

• Bighorn sheep are ruminants
• Will chew on food all day
• Graze on plants like
• Shrubs Mountain Mahogany, Silktassel
• Grasses - Needle Grass, Muhlies
• Forbs small leafy plant, herbs
• Will use paws to remove spines from cacti

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A Typical Year for a Bighorn Sheep
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Spring

• Ewes give birth to one lamb a year
• Ewes protective of lambs usually just for one
  year
• Lamb able to walk after 15 minutes
• 1/3 lambs survive their first summer

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Summer

• Adult males leave females and the young for the
  summer
• Graze off of plants and mineral licks
• Young lamb grow and learn quickly often playing
  games and butting heads
• Sheep move up to higher elevation as the summer
  gets hotter and hotter

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Fall

• Sheep come down from the mountains where it is
  warmer
• Males compete for females by butting heads
• Some competition can last for 24 hours
• Rams have a double layer of bone for protection

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Winter

• Winter is the hardest time of the year
• Food is scarce
• Weather is harsh
• Most yearlings die during the winter
• Lambs 3 years old usually go out on their own at
  this time

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Problems For The Bighorn

• Bighorn sheeps main predator cougars
• However disease and habitat loss is more of a
  concern for bighorn sheep
• Isolation cause bighorns to be very vulnerable
  to diseases from other species of sheep

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Disease And Ranching

• Domesticated sheep and livestock pose the most
  danger for bighorn sheep
• Bighorn sheep are unable to deal with
  domesticated strain of pasteurella
• Whole herds can be wiped out by the disease
• Ranching has also lead to a decline habitat and
  food source

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The End