Some Caribbean lizards' strong sexual dimorphism allows them to colonize much larger niches and habitats than they might otherwise occupy, allowing males and females to avoid competing with each other ...

Sue, the largest, most complete Tyrannosaurus rex in the world, lives at the Field Museum in Chicago. The specimen was named by Peter Larson, who founded the Black Hills Institute of Geological ...

Humans are sexually dimorphic, which means that males and females are, on average, different sizes. In humans, like most sexually dimorphic species, males are typically larger than females. Why does ...

Picture a lion: The male has a luxuriant mane, the female doesn’t. This is a classic example of what biologists call sexual dimorphism – the two sexes of the same species exhibit differences in form ...

Male spotted cuscus have spots, usually reddish brown or grey with white spots and a white underbelly, while females are of a solid colour ...

A new study suggests competition between neighboring primate groups may shape differences in body size between males and females.