Giraffes Solve Hidden Math Problems: Here’s How Researchers Proved It

Researchers set out to answer a strange question: can a giraffe do basic math without seeing a single number? According to a study published in ‘Scientific Reports’ by teams from the University of Barcelona and the University of Leipzig, the answer appears to be yes. Four giraffes at Barcelona Zoo, Nakuru, Njano, Nuru and Yalinga, were tested on their ability to mentally track and combine hidden quantities of food.

The setup involved two covered containers loaded with different numbers of carrot pieces in the giraffe’s sight before being sealed. A third, visibly fuller container was then emptied into one of the sealed ones. Choosing correctly meant the giraffe had to hold both starting totals in memory, mentally add the new carrots, and pick the container that now contained more, all without any final visual comparison.

Across the trials, the giraffes chose the larger total about 68% of the time and could track combined amounts of up to five items, mentally adding up to three new pieces to an existing hidden count. Subtraction was noticeably harder: when carrots were visibly removed rather than added, accuracy fell to around 57%, a result the researchers describe as close to chance.

The researchers were careful to rule out the Clever Hans effect, a well-known bias where an animal appears to solve a task by picking up on subtle cues from its human handler rather than reasoning independently. The experimenter wore sunglasses and kept a fixed, neutral expression throughout testing to eliminate unintentional signaling.

Even under a deliberate test, where hand movements were used to direct the giraffes toward an incorrect container, two of the four animals, Nuru and Njano, still chose the container holding the true larger amount. Researchers say this indicates the giraffes were genuinely calculating rather than simply following human gestures, while the other two, Nakuru and Yalinga, appeared to lean on the gestural shortcut instead.

Giraffes have small brains relative to their body size, and the study’s authors argue the result challenges the long-standing idea that numerical reasoning requires a large brain-to-body ratio. They instead point to the demands of the giraffe’s social life, tracking shifting herd membership, and its feeding strategy of judging which distant trees are worth the walk, as more plausible explanations for the skill.

Wikimedia Commons/by Charles J. Sharp