One of the things I love about my job is the constant need to problem solve. It’s an unending puzzle. How do I get a fat snake to breed? How do I help said fat snake reduce her girth so that she is healthier? How do I keep each animal’s brain and instincts engaged according to their needs? As a zookeeper, we have to think outside of the box all the time. But this week, a puzzle popped up that was totally INSIDE the box; the nesting box.
Pancake Tortoises (Malacochersus tornieri) are one of my favorite species. They are weird and funny, and they have unexpected super powers. I spray the tortoises daily to raise humidity, and this week after I sprayed them, I found this (please forgive the quality of photos, or lack thereof. I had to use the camera on my little phone):
Tortoises are not domesticated animals. Although they have the ability to learn, they operate almost entirely on instinct. Pancake Tortoises, like most other tortoises, like to dig deep in order to lay their eggs. Like, really deep. When they nest, they dig, dig, dig with their hind feet, and if they hit a hard spot, say a rock or in this case, the bottom of their enclosure, they stop. Their tortoise instinct says that a shallow nesting spot is worst than NO nesting spot. They abandon the hole and move to higher ground. That’s what happened here. She dug, she dug, she quit.
Here’s the tough bit. I don’t know exactly what conditions she is looking for. Depth, of course, but she doesn’t know how deep the soil is until she starts digging. Other factors come into play. Some tortoises (and it can vary even within a species) will choose a warmer spot. Others will prefer a cooler one. Some want shelter, some want space. So what does she want? When I add soil to make it deeper, she might choose a shallow spot. When I add water so that it holds together, she choose a dry one.
This is where it gets fun. Remember that super power I mentioned? This species of tortoise can CLIMB! They live in kopjes, which are basically giant rock piles. To visit the neighbors or make a love connection, they may need to scale a few rocks. They especially like to climb…wait for it… when they are ready to nest. So if the soil is too deep, she can climb out of the house and go on walkabout. It’s for this reason that we keep a heavy cover on the enclosure.
My solution this time was to heap up a pile of wet soil that was wider than she is long so that she would have deep soil no matter which way she angled her body. She nested under the heat lamp last time, so that’s where I built Mount Pancake. Would it work? The next morning, here she was:
A couple of hours later, I came back, and she was nowhere in sight. I found her under her hide box, but the mountain looked the same. Most tortoises and turtles cover their nests so completely that you would never know they had been there. Had she nested? I checked.
The egg was so fresh, it was still slimy. But it looks good! How do I know? The egg couldn’t have been more than 90 minutes old, and it had already started to band.
Banding is the first indicator of fertility. It’s a sign that the embryo and air pocket have begun to make their separation.
This egg was immediately popped in the chiller. Without cooling for a few weeks at 65 degrees, the egg embryo will never develop. Once placed in the incubator at 88 degrees, it will take about three months before it hatches.
Stay tuned next week when I share photos from my most recent hatching and maybe let you know if The Professor has made any inroads on wooing his lady.