Cats prefer to go under rather than over obstacles when possible!
|Domestic cats prefer to go under than over obstacles. Screenshot.|
If this white traditional Persian (much better than the 'ultra-Persian') is typical of all domestic cats, and I believe that she probably is, domestic cats prefer to go under rather than over obstacles because it requires less effort. This can only be the logical reason. And what is extraordinary if the tiny space that adult cats can squeeze through. Domestic cats really do have very squidgy bodies. Perhaps one reason is the floating clavicle (collar bone). The video is by mmeowmmia - Mia & Jerrie on TikTok.
You might have thought that as cats are such good jumpers they'd jump over as a choice when the space to crawl through is tiny. But no. I believe that this about conserving energy. Conserving energy aids in survival as less calories are bunt. That might be important if food was scarce. Just a guess.