Peter Wrege and Liz Rowland are wrapping up their research at Grand Saline Bai, in Gabon—but Peter has sent us a recording of elephants cavorting in the dark, and Liz has just seen her first daytime elephants in the bai (clearing). Enjoy her photographs, and then close your eyes and listen in on Peter’s recording:
Imagine you’re in the rainforest of Gabon, 25 feet up in a tree at 10 PM. You’re looking out over a pitch-black forest clearing, no stars, no moon. Elephants are about and you can hear them splashing, blowing bubbles, and “rumbling”:
To your right the stream pools up, and two deep pits let elephants siphon up mineral-rich water. A few less-optimal pits are nearby too, which younger or subordinate elephants make do with when someone bigger is around. A channel leads left out of the clearing and about 50 feet along is a spring that must be mineral rich. Families of elephants hang out there every night drinking, drinking, and drinking.
Right now, while you’re listening, there are 14 elephants in the clearing. A family of six huddles at the spring, two moms with their dependent offspring, including one very little calf who still is wondering about the function of this long thing hanging down in front of its face! Another family of three is at a secondary spring a bit closer to the stream and the pool. Two young males are far off to the right hanging out at the periphery because of the three big males in the center of the pool.
Here’s a guide to what you’re hearing in the sound clip—a sample of what we experience every night on the platform. There are lots of sloshing sounds as the animals move around a bit and lift their trunks out of the water to drink. When we need to, we use our night-vision binoculars and infrared spotlight to see what is going on. But much of the time we are in the dark, so to speak.
00:40 One of the males gets chased out of the pool by a bigger male.
00:59 A loud, deep rumble from the biggest male in the pool.
1:22, 1:39 Males in the pool are blowing air out of their trunks to clear sediment out of the mineral pits, then siphoning up another drink.
Here’s a visual depiction, or spectrogram, of the sound clip.
Elephants have deep voices, so I’ve set the graph to show only the lowest 300 Hz of the frequency range—that means the higher-pitched night calls and splashing sounds don’t show up. What is really cool is that the microphones picked up three other rumbles—two before and one after the one that we can hear on the recording. They were so low that you and I can’t hear them at all (I’ve indicated them with arrows on the spectrogram). I think the short rumble just before the male’s is what triggered his call. We will have to wait until we get back to the Cornell Lab with all of the data from the acoustic array before we can find out just who gave those other rumbles!
Liz’s Morning Treat
Although we’ve seen many elephants now at night, I’ve been keen to see them in the daylight, wihtout the greenish cast of my night-vision binoculars. Today was my chance. I was at the end of my nighttime observation shift. Dawn had broken; the mist slowly lifted, and colors gradually returned to the bai. The morning chorus of birds greeted the day. Bleary-eyed, Eugene and I started to pack up when we heard the tell-tale sound of rustling leaves on the far bank opposite us. A family group of eight elephants appeared on “south stage.” They seemed nervous but gradually came to the pond in front of us.
We saw one large adult female with small tusks, along with a smaller adult female, sub-adults and juveniles—all different colors, depending on what mud they’d been washing with or wallowing in. They still seemed nervous as they milled about the pond. Then a young adult male elephant approached with apparently one thing on his mind—females. The big adult female seemed to be having none of it, though, and kept chasing him off. The rest of the group climbed the bank and headed out of the bai, as if the female had told them to leave. She followed, turning back to head off the male, and to retrieve one of the group that had got left behind. A few moments later, they were all gone.
It happened very fast, but I did get to see elephants in the daytime!
(Images by Liz Rowland and Peter Wrege)