ectozoochory

Ectozoochory, also called epizoochory, is a mode of seed dispersal in which diaspores adhere to the exterior surfaces of animals (fur, feathers, or exoskeleton) and are transported to new locations before detaching.

Adhesion occurs through hooks, barbs, or spines on the diaspore, as well as sticky secretions or entanglement with fur or plumage; seeds may attach during contact with an animal moving through vegetation. Detachment often occurs when the animal rubs against objects, grooms itself, or loses hair or feathers, or when the seed eventually falls off during travel.

Vectors include mammals such as deer, sheep, and other ungulates, as well as domestic livestock, carnivores, and birds that carry seeds on their bodies; movement by these animals can transport diaspores across landscapes and across barriers.

Ecological role is to contribute to colonization of open habitats and forest edges, and it can be especially important in disturbed habitats, deserts, and grasslands. Well-known observably attached seeds come from plants with burrs or spiny fruits, such as burdock (Arctium), beggar-ticks (Bidens), and cockleburs (Xanthium).

Compared to endozoochory, which involves seed passage through a digestive system, ectozoochory involves external attachment rather than ingestion and excretion. Its success depends on animal movement patterns and grooming behavior, and it can be less reliable under some conditions. Research often focuses on seed morphologies that promote adhesion, the behavior and ranging of host animals, and the resulting patterns of plant dispersal across landscapes.