exozoochory

Exozoochory refers to seed dispersal by animals via the exterior of their bodies. It is a form of zoochory, distinct from endozoochory where seeds are ingested and later excreted. Exozoochorous seeds attach to fur, feathers, or other surfaces and are transported as the host animal moves through the environment. The process relies on structures of the seed or fruit that promote attachment, such as hooks, barbs, spines, or sticky secretions, and on the movement of animals that contact vegetation.

Most common vectors are mammals and birds. Seeds known to exhibit exozoochory include burrs and other hooked or sticky propagules that cling to fur or plumage, or plant propagules with adhesive surfaces. Transport distances can be large if animals migrate or roam widely, enabling long-distance dispersal and colonization of new habitats. Detachment typically occurs through grooming, rubbing, or natural shedding, or when the seed encounters a suitable substrate where it becomes detached or embedded.

Ecological significance: Exozoochory contributes to plant spread in heterogeneous landscapes, helps maintain gene flow between plant populations, and can aid in recovery after disturbance. It may interact with endozoochory and synzoochory to form a multi-modal dispersal strategy.

Limitations and variation: Attachment probability depends on host behavior, fur or feather texture, and seed morphology. Not all plants have traits enabling exozoochory, and effectiveness can vary with season and animal community.