Similarities:
* Both squirrel monkeys and humans have a backbone, a skull, and four limbs.
* Both squirrel monkeys and humans have a ribcage that protects the heart and lungs.
* Both squirrel monkeys and humans have a pelvis that supports the spine and provides attachment points for the muscles of the legs.
* Both squirrel monkeys and humans have hands with five fingers and feet with five toes.
Differences:
* Squirrel monkeys are much smaller than humans. The average squirrel monkey weighs about 1 pound, while the average human weighs about 150 pounds.
* Squirrel monkeys have a longer tail than humans. The tail of a squirrel monkey can be up to twice as long as its body, while the human tailbone is only about 1 inch long.
* Squirrel monkeys have four premolars on each side of their upper and lower jaws, while humans have only three premolars on each side.
* Squirrel monkeys have a smaller brain than humans. The brain of a squirrel monkey weighs about 1 ounce, while the human brain weighs about 3 pounds.
* Squirrel monkeys have a shorter lifespan than humans. The average squirrel monkey lives for about 10 years, while the average human lives for about 70 years.
Overall, the squirrel monkey and human skeletons are similar in many ways, but there are also some key differences.