animal glue

Animal glue is an adhesive, sizing agent, and protective colloidal material derived from the hydrolysis of proteins found in animal tissues like skins, bones, connective tissues, and tendons. It is a gelatin-like substance extracted from animal parts such as hides and bones, or from fish, milk solids (casein), or vegetables.12

Historically, glue was used as early as 3000 BCE in Egyptian furniture construction. While synthetic adhesives are increasingly common, animal glue remains valuable in woodworking, the production of abrasives like sandpaper, and as a colloid in various industrial processes.2