Giraffe

Same number of vertebrae as you

A giraffe has seven cervical vertebrae — the same as a human, a mouse, and almost every other mammal. Each one is just much, much longer. The longest measure 28 cm (11 inches).

A blood pressure problem

Pumping blood up to a head 2 meters above the heart requires roughly twice the blood pressure of a human. To prevent the brain from being starved when the giraffe lowers its head to drink — a position that would otherwise cause a sudden surge of pressure — giraffes have specialized valves in the jugular veins and a network of small blood vessels (the rete mirabile) at the base of the skull that buffer pressure changes.

A purple tongue

A giraffe’s tongue can be 45 cm (18 inches) long and is dark purple-black. The dark color is thought to protect it from sunburn during the long hours it spends extended outside the mouth, gripping acacia branches between thorns.

Four (or one) species?

The IUCN currently lists the giraffe as a single species with nine subspecies, but a 2016 genetic study proposed splitting it into four distinct species: northern, southern, reticulated, and Masai. The taxonomy remains debated.

Why so quiet?

Giraffes were long thought to be silent. They’re not — they communicate with infrasonic hums below human hearing, particularly at night.