The comment you came across about pigs not being able to look up at the sky is indeed rooted in some anatomical aspects of pig physiology. Pigs, by nature, have a unique anatomical structure, particularly in their spine and neck, which is adapted to their foraging behavior on the ground.

Pigs can technically look at the sky, but not in the same way humans do by tilting their heads straight up. The anatomy of a pig’s spine and neck is designed to optimize rooting and foraging activities. Their necks can only tilt upward at approximately a 45-degree angle, making it challenging for them to look directly overhead.

The natural selection process has shaped the pig’s spine and neck in a way that supports their foraging habits. Since pigs spend a significant amount of time with their heads down, searching for food like roots, insects, worms, and other items, their anatomy has evolved to accommodate this behavior.

Unlike humans, who would find it uncomfortable to keep their heads in a downward position for extended periods, a pig’s spine is adapted to handle the weight of its head, which can be around 15 pounds. The spine curves downward as it approaches the neck, and the neck itself points outward parallel to the ground, with the natural position of the skull facing downward.

While the pig’s anatomy may restrict them from looking straight up, they have developed alternative methods to observe their surroundings, including the sky. Pigs can achieve this by tilting their heads, sitting on their haunches, rolling on the ground, or backing up to reduce the angle. For instance, when sitting on their haunches, the spine becomes angled, allowing the head to be tilted upward, and the pig can extend its view further by another 45 degrees.

In summary, while pigs may not gaze directly at the sky like humans, their adaptable behaviors and unique anatomy enable them to observe and appreciate their environment in various ways.