Wednesday, May 8, 2013

Tracking The Desert Tortoise

Living in southern Utah and hiking a lot of landscape over the past 20 years, you would think that I’d have seen at least one desert tortoise stroll past my boots. Sadly this has not been the case. The Mojave desert tortoise spends 95% of its life underground. It all comes down to chance, and whether you are looking in the right place at the right time. 

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It did not appear that anyone was home


In fact, it wasn’t until recently that I was lucky enough to observe the elusive Gopherus agassizii in its natural habitat in the Red Cliffs Desert Reserve near St. George. It helped that I was on a field trip with a wildlife biologist and tortoise specialist who knew what to look for and where to look for it. 

Our small group gathered mid–morning early in this month of May, prime time for tortoises to be active and looking for food. Much of their water is obtained in the vegetation they eat. It had rained a bit over the past few days, too, and was threatening as we hiked, so there must have been some precious water also to be found in pockets of sand and rock. 


Thunderstorms threatened but never did materialize


We walked low and slow. Who knew that by the end of the morning we would stumble across not one but three tortoises? 

 
Tortoise number one was found basking in the morning sunlight. 

A basking tortoise blends in well with its surroundings


Tortoises are known to dig catchment basins and return to them when rain is imminent. Because they lose water at such a slow rate they can survive for a year without it. 

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The basking tortoise, all stretched out and relaxed

To avoid the heat of the desert summer and the cold of winter, tortoises spend much time in burrows which they dig themselves, often extending them eight feet or more into the protective soil. They are most active above ground in the spring while spending the winter months in a dormant state in their burrow. 

Burrows are easy to walk by and never see

These resilient reptiles can live up to 80 or even 90 years, given the chance.
 
This tortoise has been tagged (yellow) by wildlife biologists

There are many reasons why the desert tortoise is classified as a threatened species, though. They are quite sensitive to human disturbances. Recent studies show that tortoise numbers have declined 90% since the 1950s, from 200 per square mile to less than 60 per in the Sonoran and Mojave deserts of California, Nevada, and Utah. Survival of juveniles is low. Perhaps five out of one hundred hatched may live to adulthood. 

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We followed these tortoise tracks up the wash but lost them in the rocks

Their populations have gone down due to habitat loss related to climate change and drought, predation by ravens on juveniles, and urban development along with its accompanying side effects such as being crushed by automobiles, the spread of diseases, a proliferation of poaching activity, and the thoughtless use of off–highway vehicles in tortoise habitat. 

 
Tortoise number two was on the move between the bur sage and creosote bushes. 

Our tortoise number two

The Red Cliffs Desert Reserve protects a substantial expanse of desert habitat capable of sustaining diverse wildlife populations, especially the desert tortoise, threatened by rapid development and habitat loss across the southwestern corner of Utah. 

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Tortoise number three was basking in the sunshine exactly where we had planned to walk. 

Tortoise number three

A minor course adjustment to a healthy distance allowed us to watch the tortoise watching us.


After a few minutes it rose up on its stubby legs and headed in our direction. I felt like we were about to be attacked by an eight inch tall tortoise even though it wasn’t exactly breaking any land–speed records.


It seemed to want to investigate our boots and came towards us even as we backed away. I suppose being so low to the ground, boots are pretty much what a tortoise focuses on.  

After following us around for a few minutes it moved past us, so we said our farewells and watched as it toodled down the hill to new tortoise adventures in the rocky red hills of the desert reserve.

Farewell for now, tortoise number three!


So now I can say I’ve seen desert tortoises in the wild.  Three in one day – it was worth the twenty year wait! 

If you happen to come across a tortoise, enjoy it from a respectful distance, and please don’t pick it up (unless it is in the middle of a highway, in which case you can move to the other side so it can continue in the direction it is going).



















4 comments:

  1. Thanks, Nina! Would you say these are about the size of a football? A pineapple? You got some really nice pictures.

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  2. Judy - I think a big pineapple with stubby feet would be a good size comparison! Very glad you like the pictures, too. Once a tortoise was spotted it was easy to snap pix (even with the zoom) since the pineapple-sized reptile wasn't going anywhere fast, unlike lizards which tend to scamper away quickly.

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  3. From 0 to 3 in one day is pretty good odds. Sad to hear about the decline in population and for the same reasons as so much other wildlife. Nice shots.
    BTW, I've been told if you do need to pick one up, hold it away from you as it will pee.

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    1. Gaely - Yes indeed, it will pee when picked up, which is probably a stress reaction.

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