Hippo Yawn


A massive hippo (Hippopotamus amphibius) bursts from underneath the water’s surface to gape at maximum extension in a display of dominance. Of the two dozen or so hippos around, this individual was noticeably the largest. To mark their territories, hippos have an unusual behavior of using their feces as projectiles. Twice this individual emerged from the depths to turn around and defecate while rapidly slapping the tail from side to side. Remarkably, these bits of airborne feces can fly as far as 20-25 meters! Like the baboons in my previous post, hippos are sexually dimorphic with males having enlarged canines for use in male-male competition. Most agonistic interactions involve gaping, charging, splashing, and low reverberant grunts, but fights may escalate into biting and slashing at the head and body. Hippos are extremely powerful animals, capable of delivering bites with a force over 1800 pounds per square inch. Due to their strength and temperamental nature, all aquatic inhabitants within their range (crocs too!) know to give way to the hippo.


On another occasion, a herd of elephants wandered in close proximity to the hippos, eliciting boisterous interactions between the hippos and towards the elephants. Elephants would individually wander toward the water’s edge and hesitate, examining the blockade of hippos cautiously. Two of the hippos repetitively gaped, one directly towards the elephant, and after some stammering the elephant left to join the rest of the herd further down the river. Although an elephant dwarfs the hippos in size, hippos are pugnacious, and an elephant wouldn’t want to unnecessarily risk injuries to its trunk or body. Earlier this month we spotted eland and kudu racing away from something alongside the river. Sure enough, moments later an angry hippo came bolting by — it was astonishing to watch how quickly this cylindrical creature zipped by on land.

All photographs in situ [1]

After yawning, this hippo performed an interesting clapping behavior, smacking its mouth against the water’s surface, almost as if it were drinking water and exhaling.

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