Additionally, the leading edge of the nictitating membrane as it sweeps across the cornea acts as a squeegee polishing the cornea, limiting the amount of lacrimal fluid left on the eye, and sweeps foreign objects off the eye before it. Mammals possess eyes that rotate in the socket. The entire eye needs to be lubricated, requiring the production of larger amounts of lacrimal fluid. The eyes of reptiles, amphibians, and birds are fixed in the skull and have very limited movement in the socket. Only those surfaces exposed to the elements require lubrication.
Humans possess tear ducts on the edge of the eyelid.
Their production of tears is distributed across the exposed surface of the eye. Thus when the exposed surface is dried out, as in riding a motorcycle, excess tears are produced to protect the eye. The resource used doesn't elaborate on which, if either, system of lacrimal distribution is pervasive in the higher orders of the animal world. However, if memory serves, the ability kof humans to express emotion through the production of tears is unique to our species. They blink the membrane rapidly and frequently.