Can toddlers sense pregnancy?

I know animals can sense pregnancy but can toddlers also?. I am unsure if I am expecting as yet. Planning to test on 1st October if cannot wait till when AF is due on 5th October. My Son has been acting out of character these past few days. He has become so clingy and want to just be on my lap continuously instead of playing and getting on with his usual toddler stuff, a lot of kisses and hugs and wanting to be held like a baby 🙄 etc. As cute as this is and I am not complaining however feeling so drained out. 😞