Long Neck Siphon Mechanism

Adult giraffes reach heights of 4.5 meters with a heart-to-head distance of over 2 meters, making cranial blood supply challenging. Duplex ultrasound confirmed that the giraffe jugular vein collapses during head movement from ground level to fully erect, negating the possibility of a siphon mechanism in the neck. We showed that in a collapsible tube, flow is significantly influenced by a short length siphon structure over a simulated head to heart distance for a giraffe, with the length of the siphon structure determined according to brain case measurements.