• Rainbow over Half Dome

    Yosemite

    National Park California

Newts Wrestling_100846

February 26, 2014 Posted by: BW - Park Ranger (White Wolf/Big Oak Flat/Yosemite Valley)
At the lowest elevations of Yosemite National Park, there is an amphibian that is making quite a scene. Sierra newts (Taricha sierrae), formerly a subspecies of the California newt, are beginning their breeding season. Like all amphibians, this newt requires water to reproduce and the males returned to their breeding pools earlier this winter.

Throughout most of the year, these newts are terrestrial, with thick warty skin and live underground or in damp places under rocks and logs. While in the pools, the newt's body changes into an aquatic phase, which results in smoother skin and a fin-like tail to assist with swimming. The males also develop rough pads on their feet. Why is this necessary? Well, the males have been patrolling the pools for weeks by the time the females show up and are eager to claim each as their own. The rough pads will enable them to grip the females better. Wiggling balls of wrestling newts can be seen as each female is surrounded by many males trying to get into position. After a male successfully grasps a female and swims away with her, he will deposit a spermatophore, which she carries to a suitable spot to fertilize and lay her eggs. Each spherical egg mass contains between 7 and 30 eggs and is attached to submerged vegetation or other underwater objects.

All this activity seems like it would draw a lot of attention, but the newts have an evolutionary trick that keeps them safe from predators. The bright orange color underneath is a signal that they are poisonous! Their skin contains glands that produce a potent neurotoxin, tetrodotoxin, which causes seizures that paralyze the heart and lungs. When the newt feels threatened, it will arch its back showing the bright color underneath its chin and tail. This signal deters many predators. Garter snakes (Genus Thamnophis), however, eat plenty of newts. They have preyed upon newts for so long; they have evolved a resistance to the toxin. This is a great example of coevolution between predator and prey, the newts and the garter snakes. Humans are sensitive to this toxin, which can be absorbed through mucus membranes and open cuts, so please do not handle newts.

A video of the action, including a female laying eggs is available on YouTube.


Newt walking on ground and swimming through water

 

Nature Scene, BW




13 Comments Comments Icon

  1. Anna - Wisconsin
    March 30, 2014 at 03:22

    Thank you for being so responsive and posting the video. I will show it to my Terrestrial Vertebrate Ecology students

  2. Yosemite National Park
    March 28, 2014 at 08:14

    @Anna, we're having technical problems displaying the video on our website, but have now provided a link to the video on YouTube. (This is a longer version of the video than appeared on Facebook.)

  3. Anna - Mazomanie, WI - Wisconsin
    March 28, 2014 at 10:04

    please bring the video back! It was great!

  4. Doug - Santa Monica Mountains, California
    March 05, 2014 at 10:04

    Taricha torosa are moving in SoCal after the rains. In the 60's, a fraternity had their pledges swallow newts as part of their initiation. Severl of the members died. Shame they didn't have a good herpetologist in the group!

  5. Yosemite National Park
    March 04, 2014 at 01:19

    @Alice, we've updated the blog to reflect the new species name. Thanks for the correction!

  6. Brian - Yosemite, CA
    March 04, 2014 at 09:38

    Thanks for pointing this out! Looks like we all need to update our field guides. Indeed, Taricha torosa and Taricha sierrae were recognized as separate species in 2007.

  7. Alice - Redding, CA
    March 02, 2014 at 12:03

    Love the Taricha genus. Interestingly, the Sierra Newt has been split off from Taricha torosa after it was discovered that at the southern part of the range, the newts were coast range newts with a very thin contact zone with Sierra newts. In that contact zone, hybridization was rare and when it occurred, nature selected against the hybrids. Thus, the sierra and coast range subspecies despite a contact zone are on different evolutionary paths and are distinct species. The Sierra Newt is now Taricha sierrae I'm still hoping to find some up here in Shasta County, the northern-most part of their recorded range, but so far just rough-skinned (Taricha granulosa)

  8. Darlece - Vashon Island, WA
    February 28, 2014 at 01:07

    Miss these guys so much! One of my favorite things about living in El Portal.

  9. B - Arlington, VA
    February 28, 2014 at 08:20

    She turned me into a newt!.....I got better

  10. Brian - Yosemite, CA
    February 28, 2014 at 12:55

    Amphibians are sensitive to changes in their environment. Worldwide, all amphibians are suffering population declines. The California newt, which is endemic to California, is declining mostly in Southern California. The primary drivers of this decline are habitat destruction caused by human activity and invasive species such as mosquitofish, crayfish, and bullfrogs which will prey on larvae and eggs.

  11. Amanda Vosper
    February 27, 2014 at 09:47

    Are these amphibians facing the same population declines as many frog species?

  12. Regina K - Chino, CA
    February 27, 2014 at 07:08

    Yes, they belong to family "Salamandridae"

  13. Fran Sanchez - Bakersfield, California
    February 27, 2014 at 03:13

    Interesting , are they related to the salamanders ?

 

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Did You Know?

View of Yosemite Valley from the Wawona Tunnel Vista.

Rockfall events have helped shape many of the outstanding features along Yosemite Valley's walls, including Royal Arches, North Dome, and Half Dome. Giant talus slopes that slant away from the Valley walls accumulate debris with each rockfall event.