Corneas are the only body parts with no blood supply — they get oxygen directly from the air

How does the unique circulatory system of birds, including the avian respiratory system and air sacs, contribute to their high-altitude flight capabilities?

Birds' efficient oxygen-exchange system and air sacs enable sustained high-altitude flight by maximizing oxygen uptake and minimizing energy expenditure

Octopuses have three hearts, blue blood, and nine brains — one central, eight in their arms

Octopuses possess three hearts, blue blood, and a central brain with arm-based mini-brains

The strongest muscle relative to its size is the masseter (jaw muscle)

Masseter: Strongest muscle by size, vital for mastication

The first photograph took 8 hours of exposure — taken by Niépce in 1826

Niépce's daguerreotype, first photograph, required 8 hours exposure in 1826

Mongolia is the most sparsely populated country — 2 people per square kilometer

Mongolia has a population density of approximately 2 people per square kilometer

The mantis shrimp can punch at 50 mph — accelerating faster than a .22 caliber bullet

Mantis shrimp's punch speed exceeds .22 caliber bullet's velocity