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Rare Giant Salamanders Bred in Captivity

By Tim Hornyak

Imagine an amphibian up to 5 feet (1.5 meters) long that can weigh 80 pounds (36 kilograms) and snap chunks off your finger in a split second.

The Japanese giant salamander is one of the largest of its kind in the world: a mottled, slimy, living fossil that has changed little in millions of years.

giant salamander picture
A captive Japanese giant salamander at the San Antonio Zoo. Photograph by Joel Sartore, National Geographic

Being nocturnal and mostly aquatic, these super-salamanders are rarely seen. They lurk in cool streams in mountains and foothills. Though once caught for food, they’re now protected as a national treasure in Japan.

Hunting, pollution, and river damming brought their conservation status to “near threatened,” but now a nature center says it has made progress in breeding the giant salamanders. (Also see video: “Giant Salamanders Helped to Spawn.”)

“Although this is the second captive breeding in Japan, it’s the first in an indoor display tank,” said Akihiro Ito of the Hanzake Nature Museum of Mizuho in Shimane Prefecture. “It took us five years.”

Breeding Challenges

Hanzake, as the creatures are known locally, reproduce by external fertilization. A female lays hundreds of eggs that a male fertilizes after doing battle with other males. The male then guards the growing larval salamanders in his role as “den master.”

But giant salamanders often don’t thrive in captivity, so conditions had to be perfect. In consultation with the Hiroshima Asa Zoo, which has also managed to breed them, the nature museum used groundwater adjusted for acidity, and carefully controlled the temperature, light, and air in the salamanders’ environment. (Also see “Pictures: Seven Energy-Smart Zoos and Aquariums.”)

Staff placed two males and three females in the tank, which had a single den, but things didn’t go well at first. A male occupying the den would attack the others; in one case, a female was viciously mauled.

After several different combinations of males and females in the tank, finally a male called Daigoro and a female called Sachiko managed to mix it up, and a clutch of some 500 eggs was fertilized.

“Knowing how giant salamanders go about breeding and what conditions are necessary for that to happen comes in useful when considering how best to protect them in the wild,” said Tim Johnson, a Tokyo-based salamander enthusiast who has observed these creatures in the mountains.

“The way rivers have been modified in recent decades has made it difficult, and sometimes impossible, for them to migrate upstream to breed.”

Congrats to the new parents; we’ll keep track of how they do with their baby giant salamanders.

Comments

  1. Medli
    U.S.A
    February 24, 1:09 pm

    So, you went to Japan, and didn’t bring me any souvenirs?!

  2. paul
    uk
    December 3, 2013, 10:09 pm

    to Alric Smith, i agree with the principle of what you are saying, but your maths is out because earth is supposedly only 4.54 billion years old not 46 billion, unless you accidentally forgot the decimal point.

  3. Kai S. Lee
    October 17, 2013, 10:05 pm

    Why are these so cute, slimy, and… well, awesome? They are aquatic, giant, and very, very interesting… interesting to watch that is. I’d bet they’d be a rare find if you get to see one!! And I mean REALLY rare.

  4. Alric Smith
    Melbourne, Victoria, Australia
    October 3, 2013, 4:49 pm

    Though I agree largely with George, I do not like the marginalizing of the titanic effort going it no saving many of these creatures, if you try to SHAME people for being consumers, they will end up desensitized verses gaining interest which, well gains there INTEREST and in a long term makes a person more concious of the effect we are having on our world…. the planet is roughly 46 BILLION years old. If we scale that to 46 years, we have been on this planet in a recognizable human capacity for 4 hours. The industrial age started 1 minute ago and in that one minute we have destroyed some 50% or more of the worlds natural habitats. Destroyed or damaged some 70% and had a negative effect on 95% of it, it isnt sustanable, but for a creature that lives for less than 0.1 of a millisecond how do you explain that?

  5. Mukul Chauhan
    India
    October 3, 2013, 12:44 pm

    It looks mutated…..

  6. cjy
    Oregon
    October 3, 2013, 12:37 pm

    So CUTE!

  7. juan zorrilla
    caaguazu py
    October 3, 2013, 11:44 am

    es una especie de lagartija y pez…?

  8. rashed
    indonesia
    October 3, 2013, 9:00 am

    well at least peoples want to hear a good news :)

  9. Sławomir Uchto
    Poland
    October 3, 2013, 1:39 am

    Does it breath fire?

  10. neal zarka
    Thailand
    October 3, 2013, 12:51 am

    Georges, you can’t blame them to describe a success without talking about all the other species, everybody is aware of this problem, also it’s not a real problem, species tend to disappear one day or another, it’s just a matter of time.

  11. Jane Hutchens
    L.A., California
    October 1, 2013, 3:15 pm

    OMG! I WANT ONE AS A PET!!!! THEY ARE SOOOOOOO AWESOME!!!!!

  12. Dorky Doo
    Nebrasca
    September 30, 2013, 6:04 pm

    I mean come on…..really?

  13. George Clark
    United States
    September 30, 2013, 2:49 am

    Similar near-extinction events are taking place around the globe for decades.

    These stories need to extracted from their human-interest motif and returned to the uncomfortable and frightening reality where they belong. These are not isolated incidents where Salamanders named “Daigoro” and his species are somehow “saved”…the end…?