Hippos

Heres a program from our archives.The hippopotamus is one of the few animals that lives in and out of water. Scientists have recently learned that hippos produce sounds especially suited to both these habitats. I’m Jim Metzner and this is the Pulse of the Planet.Ambience, HipposWilliam Barklow is an associate professor in the department of biology at Framingham State College. On an expedition to a remote area of East Africa, he recorded the hippo vocalizations that we’re listening to now.Barklow: The hippo’s lying with its head just above the surface. The nostrils are just above the surface. The eyes are above the surface. They bulge out of the head too, as well as the ear. So all the sense organs are above the surface. The mouth, however, is below the water. I watch them over and again make their loud sound, this wonderful bellow sound that the hippo makes. But I notice that when they make that sound, they do it with their head in the water. Their nostrils are above the water, but their mouth is below the water. The sound comes out of the open-valve nostrils. [and] There are no bubbles that are apparent from underwater, so no sound apparently comes from the mouth. But we recorded both above- and below-water sounds at the same time. That is, the hydrophone picked up the sound just as clearly as the surface microphone did. So apparently they’re transmitting this sound through the tissue in their throat, it’s a fatty, blubber-like tissue that is closely matched to water in its density. So the sound travels very efficiently through this fatty tissue into the water. It was very exciting to find what we referred to as an amphibious vocalization. We’ll hear more about the significance of this discovery in future programs. This archival program is part of our thirtieth anniversary celebration. If you want hear more, check out our podcast.

Hippos

They produce sounds especially suited for transmission through air and water.
Air Date:09/24/2018
Scientist:
Transcript:

Heres a program from our archives.The hippopotamus is one of the few animals that lives in and out of water. Scientists have recently learned that hippos produce sounds especially suited to both these habitats. I'm Jim Metzner and this is the Pulse of the Planet.Ambience, HipposWilliam Barklow is an associate professor in the department of biology at Framingham State College. On an expedition to a remote area of East Africa, he recorded the hippo vocalizations that we're listening to now.Barklow: The hippo's lying with its head just above the surface. The nostrils are just above the surface. The eyes are above the surface. They bulge out of the head too, as well as the ear. So all the sense organs are above the surface. The mouth, however, is below the water. I watch them over and again make their loud sound, this wonderful bellow sound that the hippo makes. But I notice that when they make that sound, they do it with their head in the water. Their nostrils are above the water, but their mouth is below the water. The sound comes out of the open-valve nostrils. [and] There are no bubbles that are apparent from underwater, so no sound apparently comes from the mouth. But we recorded both above- and below-water sounds at the same time. That is, the hydrophone picked up the sound just as clearly as the surface microphone did. So apparently they're transmitting this sound through the tissue in their throat, it's a fatty, blubber-like tissue that is closely matched to water in its density. So the sound travels very efficiently through this fatty tissue into the water. It was very exciting to find what we referred to as an amphibious vocalization. We'll hear more about the significance of this discovery in future programs. This archival program is part of our thirtieth anniversary celebration. If you want hear more, check out our podcast.