why can ants hold i think 8 times their weight and like fleas jump however many times there size. wat is this, just someting random or is their actual reasoning behind its occurence.

They have evolved that way.

Basically, the strength of an animals leg depends the legs cross secional area, the weight it carries on the volume of the animal. If you were to scale up the size of the animal the cross sectional area of the leg would increase by a power of two, the volume by a power of three. So the legs become proportionately weaker.

Skye is correct, plus it applies to muscle cross-sections. The greater the C/S of a muscle, the more force it can exert. Muscle C/S (like leg c/s and body surface area) increase to the square, while weight increases to the cube, so very small animals are disproportionately strong.

 

Mokele