Notes From the Zookeeper: Miracles

I missed last week. It wasn’t that I had nothing to say. Trust me, I had LOTS to say, but I ran out of time in which to say it. We went to see Lego Batman, and it was past my bedtime when we came home. I’m planning ahead this time.

Our zoo works with many endangered species of turtles and tortoises, and in most cases, our goal is to breed them. With few exceptions, these animals are sneaky when it comes to nesting. They create a nest chamber, lay the eggs, and then cover it up completely with any material in the vicinity. Unless you catch them digging, you’ll never find the eggs. It’s difficult in captivity, too. Sometimes the nest is hidden so well that our only clue that they have laid eggs at all is the mud on the back of their shells.

how to breed pancake tortoise

Check it out! She is digging a nest for egg-laying! Note the dirt on her back. She kicks up quite a bit of it as she digs.

Indoor enclosures are smaller, so there is less surface area to cover, but it’s still tricky. Looking for loose soil will get you nowhere. A female will soak the dirt with her own urine to pack it down. And digging straight down yields nothing. The nest tends to hook around in one direction or another to throw off predators. Luck is the best guide.

Sometimes things go wrong. It has happened to all of us. If you’ve spent any time breeding wildlife, the unthinkable will occur. It happened to my co-worker. She had located the newest nest of Radiated Tortoise eggs, but then while digging them up, she broke an egg, a large piece of it falling off in her hand.

It’s a terrible feeling, the crushing weight of all the what-ifs. What if the egg was fertile? What if it was the only one in the clutch to be fertile? What if the female never laid anymore? When I inadvertently broke an egg, I had to go to bed early. My co-worker holds our institutional record for Radiated tortoises. Doesn’t matter. It still hurts.

But maybe all was not lost? The shell was broken, an inch-and-a-half piece gone. But she noticed that the membrane inside was still intact. There was no way to wash the dirt off of the egg like we usually do. There was too great a risk of introducing bacteria through the thin and porous membrane. She chucked it in the incubator, dirt and all, and carefully balanced the broken piece of shell over the gaping hole. And hoped for the best.

And sometimes hope is not misplaced.

We call this baby “he” because this species has temperature-dependent sex determination. The temp the egg is incubated at can determine gender for many, many species. An aside, climate change can have devastating effects on such species since only a variation of 4F degrees determines gender. Another aside, I cannot spell “devastating” without help from spell-check.

Updated for extra squee:

The only evidence of his precarious beginnings is the number of scutes on his shell. All species of turtle and tortoise in the world, from the tiny Padloper to the biggest Galapagos Tortoise have the same number of scutes (scales) on their shells. There are 22 around the bottom margin (appropriately named “marginal scutes”) and 13 of the bigger ones. Native Americans even referred to the calendar as “13 moons on the turtles’ back” because there are 13 new moons in a year. But sometimes incubation issues can result in too many or too few.

turtles have belly buttons

The little zig-zag in the middle is what you’re looking for.

Meatball has a couple of extra ones, referred to as “split scutes.” It is a purely cosmetic issue and only adds to his charm.

Updated a second time to include the best shot of tortoise tushy EVER!

how tortoises hatch

TUSHY!!! Look at those chunky thighs!

I hope you have a great week! What are the miracles in YOUR life?

Playing Favorites

I admit it. I know I’m not supposed to, but of all the little ones, I have a favorite. Don’t tell the others, please.

Astrochelys radiata, the radiated tortoise

I know that all the babies are adorable, but this one has a special place in my heart. The population of the radiated tortoise (Astrochelys radiata) has dropped by half in the last ten years. They have been wiped out of most of their range, so captive breeding programs are of critical importance. She’s the second one my zoo has hatched.

I call this one “she” because she was incubated as a female. Many reptiles have what is called temperature dependent sex determination. When the egg is first laid, the embryo within has no gender at all. The temperature at which it is incubated has an impact on whether they develop into boys or girls. Keepers can often produce the gender they need by altering the temperature at which they incubate the eggs. With this species of tortoise, higher temperatures usually yield more females. Lower temperatures tend to create males.

A perfectly proportioned tortoise in a tiny package

Here she is with her older sibling who was hatched in July. I have no idea whether the older one is male or female. Its egg incubated outdoors for a bit, so it was subject to unknown temperatures. Radiographs in a few years can tell if we’ve got a boy or a girl.

Pesky little sister

One thing I really enjoy about this baby is her personality. She is all go. I have no good recent pictures of her because she won’t sit still. From a biological standpoint, her curiosity isn’t a good thing because she might get eaten, but in captivity, it’s positively delightful.

I’ll be back on Monday full of my tales of adventure. And hopefully with some new pictures. Have a great weekend!