"My2YearOldCatLikesYoWalk."
Both are equally strong, but the second option is much more difficult to be recognized by an automatic system than the first.
The second one looks pseu-do strong but in fact it is not. It is more vulnerable to bruteforce process because you don't know what are bad guys who intend to steal your passwords.
If it is people around you and know you love cat and some other information about your cat, he will put words like "cat" "2" "old" into inputs of brute force and make it becomes more easily to bruteforce your passwords.