How are pronghorn antelope capable of running so fast and so long?

Asked by Rockland Elementary
Answered by Alana Jensen, Environmental Educator, INL ESER Program

Pronghorn antelope are the fastest land animal on North America and the second fastest land animal in the world, with only the cheetah reaching faster speeds.  But, pronghorn can sustain high speeds for miles, and in a distance run would easily beat a cheetah without breaking a sweat.

Pronghorn expert,University of Idaho professor John Byers, says that pronghorn can accelerate from a standing start to quickly reach top speed close to 60 miles per hour.  They can maintain a speed of 45 miles per hour for many miles.  They are built to be both sprinters and distant runners.

The amazing running abilities of the pronghorn are due to some very interesting adaptations.

  • Pronghorn bones are very lightweight to allow for maximum speed, but very strong.
  • Their front hooves are larger than the back ones, and they have bouncy pads that cushion the leg bones from impact as they run, like shock absorbers. 
  • They don’t have collarbones, which allows for wider range of front leg movement.
  •  They have very long legs, that give them a long stride. At top speed, each running stride covers 29 feet.  At top speed, a pronghorn could travel the length of a football field in 3.5 seconds, taking just 10 strides.
  • Compared to goats of similar size, pronghorn have a much larger trachea, a heart three times as big, and lungs with five times the surface area for rapid intake of oxygen and increased rate and power of circulation.

Dr. Byers has proposed that the pronghorn evolved its running ability to escape from extinct predators such as the American cheetah, since its speed greatly exceeds that of any existing North American predators.

How do your muscles get oxygen?

Every cell in your body needs oxygen to function. You get the oxygen your cells need from the air you breathe.

Once you take in a breath of air, the oxygen doesn’t just stay there in your lungs. The oxygen in your lungs enters the bloodstream from the alveoli, tiny sacs in the lungs.

The oxygen-rich blood returns to the heart and is pumped through the aorta, the large artery that receives blood directly from the heart.

From the aorta, oxygen-rich blood travels to the smaller arteries and, finally, to the capillaries, the smallest type of blood vessel.

The oxygen molecules move, by diffusion, out of the capillaries and into the body cells to produce energy.

What is diffusion?

Diffusion is the name for the way molecules move from areas of high concentration, where there are lots of other similar molecules, to areas of low concentration, where there are fewer similar molecules

There is a high concentration of oxygen in the blood in the capillaries and a low concentration of oxygen in the cells, so oxygen diffuses from the capillary into the cell.

Diffusion through a balloon

Materials: dropper, balloons, cup, things with a strong smell like vanilla, lemon juice, vinegar, perfume

1. Place two drops of one of your scents into a balloon.

2.  Blow up the balloon and tie it off.

3.  Place the balloon on a cup and let it sit there for 10 minutes.

4. After 10 minutes, smell the cup.  Did the scent diffuse into into the cup?

5.  Repeat the experiment with other scents.  Did all of your scents diffuse through the balloon?

The balloon has tiny pores or openings on its skin.  Air diffuses from areas of high pressure inside the balloon into the lower air pressure surrounding the balloon.

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