An important reason some animals have bright colours and brilliant patterns is that ............... .

It is traditional to portray dinosaur skin as grey, the
reason being that big animals today, such as rhinos,
hippos and elephants, are so coloured. But all of these
mammals are colour-blind. Bright hues do not evolve
among colour-Blind species. Bright colours do evolve in
animals that can see colours and that evolve rapidly;
among such animals, many different species live
together, and each species needs a unique way to
advertise for mates. Birds are the best example. In each
tropical habitat today, dozens of closely related tropical
bird species must attract desirable mates from the
appropriate gene pool. Brilliant patterns on the male
birds are the rule. Did dinosaurs see colours? The
closest living dinosaur relatives are birds and
crocodilians, both of which can distinguish colours.
Dinosaurs almost certainly were very birdlike in being
visually oriented, colour-sighted animals.