Hatchling

From Tardis Wiki, the free Doctor Who reference

Young Zygons were called hatchlings, and were slimy and pale with shorter limbs to their adult counterparts. Hatchlings were mute, but much faster than adults. (PROSE: Sting of the Zygons) These were not as aggressive as older Zygons. At the start of their lives, Zygons had an almost white colour, had no suckers, and were more feminine and graceful.

Sterilisation later led to a Zygon's more stocky and masculine appearance, as well as their suckers. (PROSE: The Bodysnatchers)