A small piece of litter can become an animal hazard
In a park built around live-animal habitats, the boundary between guest areas and animal spaces cannot be treated as perfectly sealed. A straw dropped near a walkway may be carried by wind or runoff, while a loose lid can be picked up by an animal that mistakes it for something edible. If swallowed, plastic can obstruct the digestive tract or cause choking; even before that, a lightweight object can be difficult to spot and remove from a habitat.
Why replace the straw, rather than rely on cleanup?
Cleanup helps, but it works only after litter is noticed—and a thin straw can be easy to miss. Replacing plastic straws with paper ones reduces the chance that this particular item will remain intact in the environment if it escapes collection. Paper is not harmless litter, and the policy cannot prevent every hazard, but it changes what is most likely to reach an animal when a straw is dropped.
That is the practical logic behind the rule: in a place where animals are part of the setting, a disposable item is also a possible object in their habitat. A simple change at the drink counter can reduce that risk before cleanup is needed.
