Giraffes are so stoic that many researchers once thought the animals were totally mute, making their romantic ventures something of an enigma.
Now, a pair of scientists has learned something new about the tall creatures’ flirting strategies: Male giraffes nudge the females and sniff their genitalia. If the female is interested, she urinates. The males then collects that urine in his mouth and inhales deeply, in order to discern her availability by way of ovulatory pheromones.
“They have to nudge the female, effectively saying, ‘Please urinate now.’ And often she will,” said Lynette Hart, a researcher of population health and reproduction at UC Davis and the study’s lead author, in a university release. “He has to elicit her cooperation. If not, he’ll know there’s no future for him with her.”
Giraffes are the sole ungulates that breed at any time of year. But endless open season has a drawback, as males don’t know when any given female is available. The animals rely on a behaviour known as the flehmen response to inhale deeply through the mouth, taking in pheromones related to the female’s ovulation cycle.
Other animals (including cats, horses, and dogs) have this response, but typically wait for urine to hit the floor before interrogating it, according to the researchers. That’s not an option for super-tall giraffes.
“They don’t risk going all the way to the ground because of the extreme development of their head and neck,” Hart said.
Giraffes can grow up to 19 feet tall. Their necks can be 2.13 m long. They’re so tall they sometimes get struck by lightning, basically becoming fuzzy lightning rods in open grasslands. The researchers suspect giraffe males would rather take in pheromones (and urine) straight from the source, rather than letting it get all the way down to the ground, where it becomes harder for them to reach. The research is published in the journal Animals.
The observations of the giraffes used for this study took place in 1994, 2002, 2003, and 2004. In total, the team documented 102 instances of a male giraffe investigating a female’s genitalia; of those, 54 females urinated, and 51 times the males responded by flehmening.
Besides the, uh, unconventional courtship, the team detailed some other previously unknown or underemphasized giraffe behaviours. Previous research had noted that giraffes will sometimes chew bones, an exercise known as osteophagia. The new work found numerous instances of giraffes apparently searching for bones and gnawing on them. They even documented cases of the animals getting bones stuck in their mouths.
To be clear, the towering creatures are herbivores; they can eat up to 75 pounds of food per day, primarily in the form of acacia leaves, which they remove from trees with their long, prehensile purple tongues. Chewing bones may provide them with nutrients they aren’t getting from their green diets. The study authors noted that lactating crested porcupines chew bones, potentially to boost their calcium and phosphorus levels, and giraffes may do so for similar reasons.
Giraffes keep their secrets close to their patchy chests. In 2021, researchers found that the animals may have a matriarchal social structure comparable to that of elephants or orcas. The same year, scientists announced the discovery of short-legged ‘corgi’ giraffes, about half as tall as their ordinary counterparts. And the animals rarely vocalize, hence some scientists thinking the animals were mute — but the new research documents a case of a male giraffe’s growl.
The study details an instance in 2002, when a male let out a loud growl during a mating sequence, scaring the surrounding giraffes away from the nearby watering hole. Another example, in 2004, involved a male snorting during a fight.
These iconic African mammals apparently remain little understood, despite their conspicuous presence in savannas. Sadly, giraffes are listed as vulnerable by the International Union for Conservation of Nature, and their population is declining due to habitat loss and hunting.