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Monday, January 16, 2012

Newt Tracks

Tracks at edge of Newt Pond, San Mateo Co, California, 12/29/2011
Total width 3.8 cm, width of central drag mark 3 mm
footprints 1 cm wide x 1.5 cm long
Probably a track of the coast range newt
This is the track of a tail-dragging animal leaving the Newt Pond. Snakes don't make footprints, our local lizards usually don't enter water, and anyway, it's too cold this time of year for reptiles. Since I know that coast range newts breed at this pond every winter, this is probably a newt track, but why was it leaving its breeding pond in December?

When it comes to interpreting animal sign, observe the where, when and size of the marks, and look around for other clues. By absorbing the nature of the site in addition to observing the actual marks, you can make a good guess at the behavior of the animal.

Tracks on dirt trail, San Mateo Co., California, 12/29/11
length approx. 0.5 to 2m
I saw more tail-drag marks on the same late December day except these were far away from the ponds. Dozens of these tracks crisscrossed a dusty trail at the margin of a grassland and a forest. I've never seen so many narrow straight tracks in one place.

Edge habitat of the wandering tail-dragger
Each long track was about 1.5 to 3 mm wide and wedge-shaped in cross-section. I couldn't make out any clear footprints although sometimes I could see smudges on each side of the drag mark. The long marks reminded me of snakes, but without limbs snakes move by a variety of wave-like motions and do not leave long straight tracks.

No distinct footprints but wavy depressions on each side of the ambling track
Again, I thought of lizards, especially at this sunny margin near the cover of low shrubs. But the last lizard I saw was a huge alligator lizard in October. It was soaking up the sun on the same trail about 1/4 mile uphill, but it was barely able to move in the cool autumn air. It's possible that some lizards may be coming out of their winter torpor in the unseasonably dry and warm weather we are having, but I haven't seen any in weeks. Even with the warm days, the nights are too cool for reptiles and most of them are probably sticking to their winter hibernation.

Tracks on dirt trail, San Mateo Co., California, 12/29/11
width of drag mark 1.5 - 3mm
We haven't had any significant rain since October and one of the springs on the Dipper Ranch has already gone dry.  It's a little worrisome.  If this keeps up, the cattle may have to leave the property in early spring and I may be washing clothes at a laundry mat.

Similar tail-drag tracks near the Monotti Pond 8/31/08
During the summer, these could be lizard tracks
Hours later when I returned on the same route at dusk, I came upon a newt rambling trailside. Then, a few darker minutes later, I saw two more newts trundle out from beneath shrubs on the trail's edge. Huh, I thought, not what I would expect to see on a dry December evening. This time of year, I usually see newts in the ponds. Sometimes on a rainy or foggy winter day, I might see them wandering through the grasslands or forest near water. All three newts had the rough skin of their terrestrial phase rather than the smooth slimy skin they develop once they've taken to their breeding ponds. I reached over and picked up one of the newts, set it on the trail, and it immediately started moving downhill. Sure enough, it left a nearly identical tail track.

Tracks crossing the trail in every direction, it must have been a busy December evening.
So even without rains to call them out of their summer burrows or forest floor hideaways, the newts are coming out, although not necessarily making straight tracks to their breeding ponds. Perhaps, they are just too hungry after their long summer retreat and are hunting above ground under the cover of night. Two years ago on January 16th, we took a night walk along the same route in a gentle rain and saw over 250 newts patrolling the grasslands, and many of them were eating earthworms and insects.

We saw dozens of newts eating earthworms on a rainy night in January 2010
While noodling the internet for photographs of salamander versus lizard tracks, I found an interesting paper which evaluated tracks of the California newt in different substrates. Newt tracks across exposed wet mud showed clear impressions of the toes. Tracks made on dry sloped sand rarely retained toeprints since the loose material quickly slumped into the original depressions - this seemed close to the substrate and track conditions I was seeing at the Dipper Ranch.

Although this information and the associated photographs were quite useful for my purposes, why, I wondered, would a scientist run ten California newts up and down different substrates over 200 times? Leonard Brand, a natural sciences professor at Loma Linda University, was using this information to assist in interpreting fossilized tracks found in the Grand Canyon. He concluded that at least some of the fossilized tracks were made underwater although other scientists disagree. Some Young Earth Creationists have used Brand's studies to conclude that the Grand Canyon was formed suddenly by the biblical flood rather than after long periods of sedimentation and erosion.

Newts - mystery and controversy swirl around them.

The Newt Pond has shrunk to its lowest size in years, 1/14/12
I went back to the Newt Pond on Saturday to check for more signs and, to the best of my scientific abilities, confirm that these were newt tracks. Still no rain and the Newt Pond has shrunk to a big puddle. The water can't be more than a few inches deep, but I did see two newts poking about its muddy depths.

Tracks crossing the muddy edges of the Newt Pond, 1/14/12
Saturday, there were lots of tail-drag tracks around the pond and the ones on firmer mud showed detailed toe prints. Some of the tracks showed 4 toes and some showed 5 toes.  Newts have 4 toes on the front limbs and 5 toes on the rear limbs. Lizards have 5 toes with long claws on all limbs. Although it is possible that not all the toes were registering on some of these tracks, it puts the tracks further in the camp of newts.

Five-toed prints (rear feet) in the center of photo
A four-toed print (front foot) in the center of photo
The newts appear to be leaving the Newt Pond. Will they give up on breeding this year or will they come back if it rains? I find myself wishing for rain. At the same time, I want to accept California's unique wet/dry climate and occasional droughts which shape our landscape and the native animals and plants that live here. Coast range newts have remarkable adaptations to live in both dry and wet conditions whether you think they gained these traits through evolution, intelligent design, or both.

I don't know why I have never noticed newt tracks before. Maybe their tracks are usually washed out by the rain - rain which we are not having this year. The newts are so obvious when they are breeding in the ponds, we don't think about what they are doing the rest of the time. Certainly the newts have been moving between their terrestrial and aquatic habitats twice a year all along and probably feeding along the way. Maybe it's one of those things that once you figure it out, you start seeing it everywhere.

Newt contemplating the shrinking edge of the pond
January 21 update:  here's a bonus photo taken by Susan Gold, a docent with the Midpeninsula Regional Open Space District, on Spring Ridge Trail at Windy Hill Open Space Preserve on December 29, 2011 - the same day I saw all the newt tracks above.  Susan said early that morning she saw106 newts at Windy Hill.  Something was going on that day.

Newt battle photographed by Susan Gold at Windy Hill
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This post got started a few weeks ago when I quickly put up a bunch of December photos per a discussion I was having with Katie at Nature ID about animal sign. We had a rollicking good conversation at her site about the clipped branch tips she was seeing especially when Random Truth joined in who also has a good series on Who Chews.  I will try to get up information about the other photos soon.  Bear Tracker is a good website for finding photos of animal tracks including lizard. Dirttime has photos of newt tracks.

coast range newt - Taricha torosa torosa
California alligator lizard - Elgaria multicarinata multicarinata

2 comments:

  1. Awesome, Cindy! I knew I've seen these kinds of tracks before. I planned to do an internet search this morning, because it's been nagging me ever since your last post... and you found the answer.

    With rain expected later this week, I wonder if winter will finally arrive in our parts. I'm not as concerned about winter rains as I am the potential for wildfires this summer. I imagine the local flora and fauna have adapted to our CA weather conditions, but us humans aren't too keen on wildfires.

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  2. thak you for your posts! spent the day wandering in the vicinity of schiller lake. there were many newts in the lake, which i enjoyed photographing. thanks to your posts, i was able to learn about them!!!! chris 4-22-12

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