The most distinctive characteristic of
Quasipaa spinosa are the keratinized skin spines in the chest of males. It is dark brown in colour, interspersed with dense, yellowish mottling.
Quasipaa spinosa are moderately large frogs: males grow to a snout–vent length of about and females to or more, up to in snout–vent length. It is the largest frog in
Hong Kong. Later studies has shown that usually males are larger than females, but with considerable overlap between sexes. Body size is positively correlated with maximum temperature and rainfall. Mean body weight among males may reach at least .
Quasipaa spinosa breeds in streams, laying the eggs in water under stones. Population demography of
Quasipaa spinosa has been studied for two populations in the
Tai Mo Shan Country Park in Hong Kong. These populations exhibit high site fidelity. Populations have low densities (13–42 frogs per 100 m of stream) and female-biased sex ratio. Each female produced an average 1.26 juveniles that survived until the age of 2 years. Annual survival was low, 38–65%. ==Utilization==