Sunday, May 16, 2010

Building a tortoise burrow

I haven't been posting much because I've been preoccupied with various projects -- one of which is training my permanent replacement at work. Pretty soon, in about 3 weeks actually, I am going to be officially out of a job. Just in time for summer.

Another -- less serious -- project we've been working on is building a tortoise burrow. When I was a kid in northern California our pet desert tortoise didn't have a burrow. Even in the winter months, when it hibernated, it just found a place to hide under some leaves. In the summer it walked around the yard all day. Of course, it doesn't get very hot or cold in Palo Alto.

As we all now know, the Mojave desert is a little different. And desert tortoises, being reptiles, don't like extremes of temperature. In the wild, they dig themselves 6-foot long summer burrows and up to 30-foot long winter burrows!

We're not going to provide any 30-foot burrows for our foster tortoises, but I'm very proud to say we have now created a 6-foot burrow.

In case anyone reading this would for some reason also want to build a tortoise burrow, I'll describe how we did it. On Friday we began digging a trench halfway across one of the pens, under the cement rim that borders the pen, and 4 more feet out into the dirt yard. (Since the burrow is underground, it is OK for it to extend outside of the pen.) Here are my "helpers," watching as the trench takes shape.



The next day (Saturday) we bought a pick axe to help us dig. Our soil is terribly hard to dig -- very compacted. Also, even though Rocket Boy's broken elbow has healed, he still has to be careful with it. So I actually did most of the digging. I tested the burrow's size by putting a tortoise in it to see whether she would walk up and down it. She did.



Then, when the trench was almost 2 feet deep at its lowest point, we added a length of 12-inch PVC pipe, cut in half. (Incidentally, finding 12-inch PVC pipe in Ridgecrest was NOT easy, and the tale of how we found it is worthy of its own blog entry except that I forgot to take any pictures.) The PVC pipe formed the walls and ceiling of the burrow, so that the whole thing wouldn't collapse. At the end of the trench we put a plastic laundry bucket, cut down and with a half-circle cut out of it so the PVC pipe could fit in it. That formed the "turnaround" part of the burrow, which is where the tortoise turns around so it can head back up and out again.



The next day (Sunday) we filled the trench with dirt. Here is one of my helpers, watching the trench fill up.



And then we let the tortoises try it out. This is a terrible photo because of the glare, but basically this is the entrance to the burrow (inside the pen).



This tortoise sat there for quite a while before it deigned to go down the ramp into the darkness, but eventually it did. Later in the day I went out to check on them and there was not a tortoise to be seen! They were both in the long burrow. (I should note that we have temporarily removed the divider between the 2 pens.) Then one tortoise came out again. In the early evening the other one poked its head out of the long burrow, but then went back down again.

We think we have a winner here. Tomorrow I have to start digging the second burrow. It got to 94 today. Summer is coming, we must be ready.

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