This depends on the species of crawfish. Sometimes the male and female are the exact same colors.
They show off their bright colors to the females.
The male has the brightest feathers, as they like to show off to females.
Female birds are always lighter in color and not with bright colors. Male birds have bright colors to attract the females.
The females usually tend to have dull colors while the males have brighter colors. For example the Northern cardinal.The males red while the females brown.
Male Betta's have much longer fins and normally have brighter colors and are bigger than the females.
Males have long, flowing fins, and the females have short fins. Females also don't usually have bright or a lot of colors unlike the males.
Male birds often have bright colors, while the females look more camouflaged to keep them safe.
Male neon tetras are typically more slender and have brighter colors compared to females. Females tend to be slightly larger and have a rounder belly, especially when they are carrying eggs. Additionally, males may have a more pronounced blue stripe on their body compared to females.
Male cheetahs are generally larger than females.
females
Because as in most species, the male wears the colors to attract a female mate. An example is the mallard duck. The male is beautiful color while the female is usually brown. Male peacocks have the plumage as well.
In monarch butterflies, the male and female can be distinguished by their physical characteristics. Males typically have more vibrant colors and possess distinctive black spots on their hindwings, which are absent in females. Females are generally larger and have thicker bodies, with broader wings. Additionally, females have a slightly different pattern of wing coloration, which can help in identifying the gender.