The Great Leapers

Positional Behavior

• body postures and movements
• movement is direct correlation to posture
• How and Why and Who are the leapers?

posture

• Resting Postures
• "Mobile" Postures

adaptations

• contilevering
• tail suspension
• ischial collosities
• Most adaptations are from the active body 

Leapers

• Strepsirhine primates
• Tarsiers
• "Forceful, upward parabolic leaps"
• Anthropoids "tend to leap outward along a horizontal plane"
• Archicebus achilles, Ida

Untitled Slide

• Leap frequently
• Size is limiting (not many leapers after 10kg)
• Elongated hind limbs
• Huge quadracep muscle
• long lumbar region

Example Argument

• Elongated calcaneus & navicular bones higher on foot
• morphological compromise between mechanical demands
• Long Lever Arms = Long Feet
• must be able to grasp and leap

Which group of fossil primates shows evidence for leaping?

• Omomyoids
• Adapoids
• All of the above