Thunder Lizards

From Glen Cook Wiki

Basically, dinosaurs. The term is used broadly to refer to a range of creatures which roughly correspond to pteranodons, tyrannosaurids, and so forth. Their hide is legendarily tough and is supposedly required for the soles of Karenta military spec boots.

The variety directly seen in the series are bipedal, man-sized, carnivorous lizards which apparently resemble small theropods (carnivorous dinosaurs) not unlike a velociraptor. They will eat only live prey, preferring to turn on each other before they will eat carrion. They are extremely vicious hunters which work together in groups, and are favored by the very wealthy for security (e.g. Chodo Contague). Unlike dogs, however, these Thunder Lizards cannot be trained; mansions such as Chodo's use enchantments to protect specific pathways or points of access. Another drawback is the fact that they are cold-blooded, making them sluggish when it is cold outside.