Thomisidae do not build webs to trap prey, though all of them produce silk for drop lines and sundry reproductive purposes; some are wandering hunters and the most widely known are ambush predators.

Individuals of some species, such as Misumena vatia and Thomisus spectabilis, are able to change color over a period of some days, to match the flower on which they are sitting.

Some species frequent promising positions among leaves or bark, where they await prey, and some of them sit in the open, where they are startlingly good mimics of bird droppings.

In each case, crab spiders use their powerful front legs to grab and hold on to prey while paralysing it with a venomous bite.

[9] In other cases, the difference is extreme; on average, female Thomisus onustus are more than 60 times as massive as the males.

The gravity hypothesis states that the smaller size allows the male to travel with greater ease, providing him with an increased opportunity to find mates.

[10] Other hypotheses propose that sexual size dimorphism evolved by chance, and no selective advantage exists to larger females or smaller males.