Fun Friday: Hatching Season Begins

In my job, each season brings its own mystery and magic. In the winter, many species lie dormant waiting for the warmth of spring. In summer, they are at their peak of activity, breeding and otherwise. In fall, they begin the mysterious process of shutting down for the winter to come. And spring itself? That’s the time of renewal. It’s at this time of year that when we check the incubator, we often see eyes staring back at us.

This year, hatching season got off to an early start. Our adult Pancake Tortoises (Malacochersus tornieri), a species native to countries in southern Africa, such as Tanzania and Mozambique, begin laying their eggs in the fall. This species is unusual, both in their day-to-day behavior and in their breeding. These tortoises can climb. And I don’t mean a little bit. They live in rocky kopjes, and they are gifted with the ability to scale rocks.They are also squishy. Their carapace has numerous fontanels that never close up, which allows the tortoise to squeeze into tight spaces between rocks to escape predators.

The females tend to seek higher ground when laying their eggs. They usually lay one egg at a time, and may lay 4-5 eggs over the course of a 4 month laying period. The eggs are huge at about 42mm (1.7 inches), impressive when you consider that the female is only around 6 inches long.

Here’s where things get weird. If a keeper were to place the egg into the incubator at 88 degrees, nothing would happen. Like, ever. This species experiences a diapause at the beginning of its development, which means it is laid in a state of suspended animation. Nothing happens unless conditions are right. Guess what the right captive conditions are? A wine chiller. The eggs are placed into a chiller at 65 degrees. Though other zoos do it differently, we’ve learned that a week or two at these cooler temps is all they need to get them going. After chilling, the warmer temperature of the incubator breaks the diapause and development begins. Diapause presents differently in many species, and one day I’ll do a post just on that. It’s weird and wonderful, setting up the juveniles to hatch at times when conditions in the wild are ideal for their survival.

So now pictures! Click any image to enlarge.

The hatchling waits until most of its yolk is absorbed to begin emerging.

The hatchling waits until most of its yolk is absorbed to begin emerging. This egg was laid in October and hatched in January. Incubation lengths vary widely depending on methods used. Note the completely shredded appearance of the egg. The hatchling did all that with just its egg tooth.

Calcium aids in muscle contrations. After a long rest, they begin to eat the egg shell, possibly for a calcium boost.

Calcium aids in muscle contractions. After a long rest, they begin to eat the egg shell, possibly for a calcium boost.

Happy Friday! I have more pictures and species to share soon. So far this year, we’ve hatched 10 individuals representing 3 threatened or endangered species.

What’s the good news from your week?

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29 thoughts on “Fun Friday: Hatching Season Begins

  1. CHOMP! I love those little guys! It would be a daily struggle not to pop one in my pocket and *accidentally* bring it home with me!

    Best news of the week…um…it got up to 50 degrees here one day and it smells like spring finally, a friend got us tickets to see a Broadway show, and one of our work Facebook posts went somewhat viral for the first time since I started working there. Hooray!

  2. That picture with the turtle poking its head out of its shell is to die for. Seriously regretting not going into zoology like my six-year-old self wanted.

  3. It’s hatching time here too – my sister doesn’t like to acknowledge her birthday, or the grossness of birth, so i always send her a hatching day gift instead.

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