• picture
  • picture
  • picture
  • picture
Public Radio's Environmental News Magazine (follow us on Google News)

Sunning Hippos

Air Date: Week of

Living on Earth’s Susan Shepherd reports on the all-natural sunscreen secreted by the hippopotamus.


CURWOOD: Just ahead: one man’s roadkill is another man’s trophy—that is, if you’re a taxidermist. First, this note on emerging science from Susan Shepherd.


SHEPHERD: If we had the same sweat glands as the hippopotamus, we’d have little use for the sun blocks and anti-infection creams cluttering our medicine cabinets. Japanese researchers studying the secretions of Hippos say these hairless river horses literally sweat sunscreen. And this slow-setting lather doesn’t just protect them from the hot equatorial sun – it doubles as an antiseptic to help heal wounds as well.

Scientists at the Kyoto Pharmaceutical University in Japan recently discovered the sweat salving powers by analyzing swab samples taken from Hippos at a Tokyo zoo. They found the Hippo sweat is made up of two pigments – one red, called “hipposudoric acid”, and the other orange, dubbed “norhipposudoric acid.”

At first the Hippo’s sweat is a colorless, sticky liquid, but it gradually turns blood red and then darkens as the pigments bond to form a polymer. This plastic shell of sorts that absorbs ultraviolet light, just like commercial sunscreens. Scientists found the red pigment also makes a good antibiotic, which may explain why Hippos, when nicked and cut from their frequent scraps with rivals, don’t seem to get infections. But researchers are not rushing to parlay this sweat science into any human-friendly skin applications. That might be because Hippo body odor is far smellier than our own.

That’s this week’s note on emerging science, I’m Susan Shepherd.


CURWOOD: And you’re listening to NPR’s Living on Earth.

ANNOUNCER: Support for NPR comes from: NPR stations, and Aveda, an earth-conscious beauty company committed to preserving natural resources and finding more sustainable ways of doing business. Information available at Aveda dot com; The Noyce Foundation, dedicated to improving Math and Science instruction from kindergarten through grade 12; The Annenberg Foundation; and The Kellogg Foundation, helping people help themselves by investing in individuals, their families, and their communities. On the web at w-k-k-f dot org. This is NPR -- National Public Radio.




Living on Earth wants to hear from you!

Living on Earth
62 Calef Highway, Suite 212
Lee, NH 03861
Telephone: 617-287-4121
E-mail: comments@loe.org

Newsletter [Click here]

Donate to Living on Earth!
Living on Earth is an independent media program and relies entirely on contributions from listeners and institutions supporting public service. Please donate now to preserve an independent environmental voice.

Living on Earth offers a weekly delivery of the show's rundown to your mailbox. Sign up for our newsletter today!

Sailors For The Sea: Be the change you want to sea.

Creating positive outcomes for future generations.

Innovating to make the world a better, more sustainable place to live. Listen to the race to 9 billion

The Grantham Foundation for the Protection of the Environment: Committed to protecting and improving the health of the global environment.

Contribute to Living on Earth and receive, as our gift to you, an archival print of one of Mark Seth Lender's extraordinary wildlife photographs. Follow the link to see Mark's current collection of photographs.

Buy a signed copy of Mark Seth Lender's book Smeagull the Seagull & support Living on Earth