Why do sandbur seeds stick to animal fur and human feet?

Sandbur seeds, which belong to the genus Cenchrus, are equipped with sharp, barbed spines that allow them to function as hitchhikers for dispersal. These structures are part of a process known as epizoochory, where plants rely on the inadvertent movement of animals to spread their seeds to new locations.123

When an animal brushes against the plant, the barbed spines on the burs cling tenaciously to the animal's fur. Similarly, when people walk through areas where these grasses grow, the burs easily attach to their feet or footwear. This mechanism is highly effective for the plant, as it ensures the seeds are transported away from the parent plant, increasing the likelihood of colonization in new areas.32